The Meridian & Gnomon of the Eglise Saint Sulpice

On the first day of each season at true noon, inside the Église Saint-Sulpice, the sun hits a small hole in the window high above the south transept, and on the spring and autumn equinox, it hits a brass marker just inside the altar. 

But why, you ask? It goes back almost three hundred years, to 1727, when the parish priest Jean Baptiste Languet de Gergy wanted to ensure the exactitude of the ecclesiastical calendar, particularly Easter and the moment the bells should ring. 

Clockmaker Henry Sully was tasked with the project, but passed away before it was finished, and it was picked up years later by Pierre Charles Le Monnier. 

If you look up at the south transept window on the right-hand edge, you will notice a vertical rectangular plate. Inside is a small hole with a glass aperture and an 80-foot focus lens through which, at the exact moment when the skies are clear, the sun flows and hits a designated spot within the church. On the winter solstice, the bullseye is on the marble gnomon on the wall of the north transept, and on the summer solstice, on the brass plate below the window. 

For years and one spring, summer, and autumn after another, I have tried to see this magic moment. There have been cloudy, rainy days and funerals in front of the altar, but this past spring and again on September 23, on this first day of autumn, the sky was clear, as was the altar, and with fellow nerdy folks I stood on the steps looking down at the brass marker, and at 1:41 pm the sun began to crawl across the marble to its bullseye. 

In this week's newest episode, I share all the details on the meridian, history, and the man who brought it all to life. 

For more, check out ClaudineHemingway.com 

check out a walk through Saint Sulpice https://youtu.be/GWPrXAceTFM

Transcript

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SPEAKER_00 0:02

Bonjour, bonjour, and welcome to another new episode of Paris in Blue Blanc Rouge. I am here in Paris, of course. I'm Claudine Hemingway, and we are just coming off of a really big weekend. We had Pope Leo the 14th here. I always want to call him Louis XIV, and when I wrote something the other day on Instagram, I actually said Louis XIV, Pope Louis XIV, because I'm a historian, and that's just really all I could think about and want to hear 14. I think of Louis, not Leo. But I corrected it. But it was a really big weekend. I was supposed to go and see him on the Champs-Élysées. I had a had a seat through the Saint-Soupe, which is what we're going to talk about today. But friend sent me a message and it was about an hour and a half before the doors were getting even open, and the line was already three hours long, and there was multiple doors to enter to get onto the Champs-Élysées. And it ended up being 800,000 people. So knowing that I would have had to stand there for about six hours and wait when I had so many things I needed to get done, like this episode. And I just decided to watch it on TV. It was very cool. I'm not Catholic, but I think it is fascinating. I think the subject of the Pope in general is fascinating. I found last year when the past pope passed past Pope passed away when he died. That for some reason this show came up that was on CNN that it's called Pope, the most powerful man in the world, or something like that. And it was done quite a long time ago, like right when the last Pope was picked. And it was, it's, I think, five or six episodes, and it's narrated by Liam Neeson. So you know it's already going to be good. But it was fascinating, and it goes from the very first with St. Peter all the way. It doesn't go over every single pope because I think there's like 270 some odd popes over time. Um, but it's really interesting to see how that role has changed. You know, even when there was the two, you know, two popes and we had a French Pope and all of this stuff. It's fascinating. I think you can find it on the HBO app. I've literally watched the whole thing start to finish, probably two or three times, and I want to watch it again. It's just it's really fascinating and interesting, and I have to be careful watching things like that because then I just want to go deep into the history of the Pope and I try to keep focused here on my stuff in Paris. But it was really exciting. There was a real interesting kind of calm in the city, and even I went I have Friday morning to the bells at Notre Dame rang, and every church in France the bells rang at 10 a.m. So the moment that uh Leo touched down in Paris, his his flight, and I wanted to be at Notre Dame because Emmanuel, which is the biggest bell, only rings on very special occasions. I think the last time it rang was Easter this year, and it's it's kind of usually only a few certain days. So I wanted to be there and it was really amazing. And make sure to check out if you don't follow me on Instagram or Facebook, cutting Blue Blonde Rouge or Blue Blonde Rouge. I put a video up there and it was really amazing because the first two minutes it was only Emmanuel, and he is just this deep, deep bong noise, and it was just started like one, you know, one ring and then another one, and then it was just Emmanuel for two minutes, and then the other ones joined in. I need to do a whole episode about the bells because it's really a fascinating subject, and how they all have names and who they're named after, and but I also did put the video up on YouTube, so I'll put a link to that um on the show notes for this episode as well as on my website, claudinehemingway.com. But today, what I want to talk to you about is something that also happened last week, and this is something that happens, and as I said, I'm gonna tell you about something about Sansou Peace today, and this is something that happens in Sansu Peace, and I have literally tried for many, many years to see this. And the first time I got to do it was in March, and then I got to see it again last week, and so I'm really excited to tell you. So, four times a year at exactly what is true noon or solar noon, you can witness a scientific and quite frankly a little slice of magic right here in Paris. On the first day of each season, the sun enters the south side of the Église Saint-Espipe through a small hole in the stained glass high above the transept, and it is exactly at the moment of the solar true noon, the sun marks a designated spot within the church. Now, for years, in one spring, summer, autumn, and winter after another, I tried to see this magic moment. There have been cloudy, rainy days, funerals in front of the altar, but this past spring and again last week on the first day of autumn, the sky was clear, as was the altar. And with my fellow nerdy folks, I stood on the steps looking down at this brass marker at exactly 1.41 p.m., the sun began to crawl across the marble to its bullseye. Now, some may know the meridian line from the Da Vinci Code. It's one of my favorites, as it includes both the Louvre and Sains Soupis, and part of the reason why I became obsessed with sans soupies a decade before I ever came here. However, Dan Brown's reference to the Rose Line or the Paris Meridian is that of a writer's imagination when it comes to the church. Ever since the Da Vinci Code in 2003 and the movie that came out shortly in 2006, a growing interest in the church wasn't exactly welcomed by the Catholic Diocese of Paris. Although they have come around, there's even now a banner referring to Dan Brown in the book that made the church so popular with the tourists. But why is this in Saint-Supils, you ask? It goes back almost 300 years to 1727, when the parish priest Jean Baptiste Longuet de Gergy wanted to ensure the exactitude of the ecclesiastical calendar, particularly Easter, and the exact moment the bells should ring as well as sinking the bells across Paris. Easter is the Sunday after the full moon following the spring equinox. Longay de Gergy was a priest of Saint-Supise in the first half of the eighteenth century. Anne of Austria may have commissioned the church, but it was Laurent de Gergy who was the father of the church we see today. During his tenure between 1714 and 1748, he began many projects, including the work on the Chapel of the Assumption and of course the Meridian and the Nouement. In 1721, Gergy, with the approval of the regent Philippe D'Orleans, created a fundraising effort for Saint Cupis to help parish members and restore the church itself. Today we take for granted how easy it is to check the time of the day, either on a watch or a phone. In 2026, we rarely even need to change the time manual each spring and fall. It wasn't that long ago that the time in your car, the microwave, the TV, and the alarm clock by your bed all varied by a minute or two. Now think back to the 18th century and thousands of years before that. In the eighteenth century they marked solar time, but it could differ city by city even by minutes. Saint-Soupice is the second largest church in Paris, after Notre Dame, but its transept is actually wider than Notre Dame by 30 feet, making it the ideal location for the Meridian and the Nou Mont. It also lacked a rose window in its transept, which was a plus. Churches built at the time normally faced west, with the sun rising at the apse and setting on the facade. This can differ greatly depending on how close other buildings are to the church and whether they block direct sunlight. Saint-Germain despre, a short walk from Saint-Soupice, has amazing afternoon light through its south windows that casts a colorful glow on the stones from the stained glass. Saint-Soupice was chosen not only for its grand size, but also for its location. The left bank had long been the center of education, creativity, and scientific life in Paris. Not far from the lower edge of the Jardin de Luxembourg stands the Paris observatory dating back to Louis XIV in 1667. It's also from where the Paris meridian begins and is today traced through the Aragon markers. Saint-Soupice actually holds two meridians, and neither is the one referred to in the Da Vinci Code. One is named for its creator, Henri Soulie, and the other leads to the Nouvelles. Englishman Henri Soulie was a master watchmaker who created a tiepiece for ships using a gimbaled base to absorb wave motion. Garnering the attention of Philippe d'Orléans, the regent to Louis XV, he moved to Versailles and set up his own atelier in 1718. In 1727, Souly began installing his meridian, which you may not notice and even walk right over. Under the inner south portal, Soule engraved markings in the stone that also correspond to those in the Paris Observatory. So faint today, they originally said the division of the line into thousandths of a vertical height, inscribed at the top. Below the line, it says degrees and minutes of the distance from the zenith to the tropic of cancer, also inscribed with numbers of distances, all in French, of course. Soule died on October 14, 1728, and was not able to complete his meridian. He was only 48 years old, but he left detailed plans for completing the project. After his death, he was buried in the church on the south side of the upper entrance to the choir, opposite the sacristy steps from his meridian. The project was put on hold after Soule's death until 1742. Pierre Charles Le Monnier picked up the mantle and brought the idea to fruition. Le Monier added a few of his own scientific ideas about the Earth's access to the initial plan. Le Monnier had astrology in his blood. His father, Pierre, was also an astronomer and teacher who immersed young Pierre Charles in the stars. With the backing of the regent Philippe d'Orléans and Languet de Gergis, Le Monnier continued the project, bringing it to life and shaping what we see today. Between 1743 and 1745, Le Monnier began installing the elements while calculating the measurements from each solstice and equinox. I know how many years it took me to finally see this, and I wonder what poor Le Monnier did if the equinox or solstice landed on a day that was cloudy. If you look up at the south transept window on the right hand edge, you will notice three rectangular plates, two vertical and one horizontal. Each has a small hole with a glass aperture and an 80-foot focus lens through which, at the exact moment when the skies are clear, the sun flows and hits its designated spot within the church. On the winter solstice, the bullseye is on the marble nouement on the wall of the north transept and on the summer solstice on a brass plate below the window. This past summer, the frescoes of the transept were being restored and scaffolding blocked the beam of light. Le Monnier originally installed three plaques with lenses on the right side of the window. They are still there today as you can see, but the lower two have been covered. The top, still active lens is at 24.53 meters or 90.48 feet from the ground. While Le Monnier was checking the measurements, he installed the middle lens at 23.92 meters or 78.48 feet to measure the summer solstice, the lowest at 21.25 meters or 69.72 feet, a little trial and error as he went. The width of the transept of Saint-Soupice was ideal for the project, but even then it was a bit too narrow. The brass meridian line, which runs at an angle bearing right from the south to the north, runs up the obelisk of the Nouan, extending the line that would have been cut off by the width of the church. The word Nou means knowledge, and the original creation was a pole much like a sundial that used a shadow to track the sun's movements, creating a shadow along lines that mark the time of the day. Le Monnier also asked engineer Claude Langlois to join the project to create the brass pieces that form the actual line as well as markers for the equinox and summer solstice. Langois was born at the start of the 18th century and became one of the most sought-after creators of scientific instruments, establishing his workshop on the Ile de la Cite until 1735 when he moved into the Louvre and set up his atelier. There, in the Grand Gallery, Langois created the brass line measuring 40.25 meters, 132 feet, and the oval disc that marks the Le Monnier meridian line. In the center of the South Portal, the faint reminder of Henri Souli's meridian remains. A few steps further is the brass square that starts the Le Monnier's meridian and the location of the June 21st summer solstice should hit. Carved in stone at Latin and Roman numerals and partially worn away is summer solstice, year 1745 for nutation, the Earth's axis, the obligatory of the eclipse. A brass plate marked the spot the sun would target on the solstice, but it suffered wear and tear from visitors and was removed in 1959. And I haven't been able to find an image of what that looked like. It's interesting that the obelisk was created as such a major focal point of the meridian, when in fact the entire objective was to find the moment of Easter, which is in fact one of the two equinoxes. On each of the spring and autumn equinoxes, the sun marks its bullseye just inside the entrance to the altar and choir. A brass oval plate, 10.5 inches long by 9.5 inches wide, sits just inside the left gate of the balustrade. Now that I have been lucky enough to witness both equinoxes this year, it was interesting to see the sun perfectly covered every inch of the desk in the spring, but last week for the autumn it was offset about an inch. The white marble obelisk stands at 10.72 meters or 35.17 feet high and was created under the direction of Langois, placed at a bit of an angle against the wall to capture the light with the sun at its lowest for the winter solstice. The face of the obelisk is straight up and down instead of a sloping angle. The top is crowned with a brass orb and cross destroyed during the Revolution and replaced in the mid-19th century. On the obelisk, around three feet from the top, is the faint symbol of Capricorn, the sign of December 21st and where the sun should shine at true noon on the winter solstice. It is difficult to spot from the ground, but check out my photos on my website. Further down and easier to see are the symbols of Sagittarius and Aquarius. On the left, the arrow for Sagittarius where the sun should hit on November 23rd, and just to the right, two wavy lines of water for Aquarius for January 21st. I now have a new mission to visit on each of these dates to see if we could spot the sun. Other brass elements included the lovely flourishes on the corner, and just below where the obelisk meets the base are two brass lizards. The lizards represent the passing of seasons and regeneration. The base itself was inscribed in Latin and French at the time of its installation, but was sadly somewhat destroyed during the revolution. On the left, it says Astronomical Numont for a reliable study of the Easter Equinox with a border of inscribed scientific tools, a few designed by Langois himself and held in the collection of the Louvre. Below in Latin, the translation is This is the task that the Holy Martyr and Bishop Hippolyte undertook, that of the Council of Nicaea entrusted to the Patriarch of Alexandria, and then occupied the attention of the fathers of the Council of Constance and Lateran. It also the task of the Roman pontiff Gregory XIII and Clement XI strove to accomplish with incredible labor and the diligent assistance of expert astronomers. The system achieves that goal by the means of the calculated meridian line and the iconical point using precise indicators derived from solar cycles. Below that was once the symbol of Virgo, which was then carved out during the revolution. Not sure what they had against astrology. Below in French has a Bible verse from Psalms 73. What have I in heaven and what have I desired on earth? God of my heart and my portion, God forever. What should I seek in heaven and what could I desire on earth if not you, Lord? You are the God of my heart and the heritage I hope for eternity. Psalm 73. The right side is topped with a paschal lamb carrying a cross and banner. The section just below was destroyed during the revolution as it referred to the king. Until last year the church had a framed description with the original markings that has since been removed. All of the chapels have new fancy plaques added in 2024, but since I take pictures of everything, I have a few. A work dedicated to God, the best and greatest, executed in a manner worthy of the crown, under the auspice of Louis XV, a generous benefactor to this basilica, and with the support and patronage of J. Fred Philippo, the Count de Morpass, Minister of State, and principal patron of the Church's endowment, as well as Philippe Aury, Minister of State, and Superintendent General of Royal Buildings. It was carried out in the name and under the council of the Royal Academy of Science by Le Monnier, a Fellow of that Academy and the Royal Society of London, commencing at the Autominal Equinox and concluding at the Winter Solstice, Years of Salvation 1743. Below that was a symbol that it was maybe Gemini and another one, but it's not for sure, and it also was completely destroyed. Behold, you have made my days and my substance measurable or nothing before thee. Psalm 38, just below that. With the base of the omelus was damaged in the revolution, the rest of the meridian line and balustrade were saved by two quick thinking pharmacists. Duchatel and Shara stood watch in front of the blue Turk and marble balustrade and convinced the angry revolutionists that the meridian line was based in science, not religion, and should be saved. Thankfully, it was. The high altar couldn't be saved. Want to see this for yourself if you're in Paris? Make sure you are in Paris with the equinoxes and the solstice, but be sure and check the actual dates for Paris as they differ from the U.S. at times. Also, the true noon or solar noon is the moment the sun is at its highest peak. The exact time could change depending on the location, day, and even the year. The next one, the winter solstice, is on December 21st and the true noon is at 12.48 p.m. The spring equinox will be March 20th at 12.58 p.m. The summer solstice is June 21st at 1.52 p.m. And the autumnal equinox on September 23rd, next year at 1.43 p.m. The parish priest behind the idea, Longues de Chergy, served until November 19, 1748, finally seeing the completion of the Meridian and the Nouan. In the final two years of his life, he served as an abbot at the Notre Dame de Bernay in Normandy, where he died on October 11, 1750. In the chapel of Saint Jean de Baptiste on the west side of the South transept, the parish created a great monument for the priest after his death. Longay de Sergy rededicated the chapel to Jean le Baptiste in 1724 and made him his patron saint. The church and Paris commissioned a large cenotaph as a gift to the man who gave so much to the church. French sculptor Micolin Schlacht submitted his idea a month after the priest's death for a fitting memorial. The priest is depicted in white marble on his knees with his arms outstretched toward the altar, also the Nouement. Above, the angel of immortality lifts the veil in the same blue Turk and marble of the balustrade of death, announcing his resurrection. Before the revolution, she also held a plan of the church drawn in gold on a bronze plaque. On the left, death lies under his large veil of marble. Sculpted in bronze, the skeletal figure holds his scythe as he turns to leave. The bronze feathers of his wings are incredible. This scene is carried out on top of a large black marble tomb sitting on a red long duck base with a carved inscription dedicated to the beloved priest. When created, Slotz included two marble genies attached to the red marble base representing religion holding the arms of Girgy. The other, charity, held a cornucopia overflowing with fruit. The entire scene plays out in front of a pink marble obelisk lying flat against the wall, very fittingly. During the revolution, Alexandre La Notre saved the monument and moved it to the Petit Saint Augustin. It did not see its return to the chapel until September of 1821. The bronze plans of the church, a laurel branch, and the genie of charity were lost and never returned. The red marble base was built in 1810 and added with a new inscription. Here rests in the lore Jean Baptiste Joseph Longa de Gergy, born in Burgundy of a noble family, doctor of the faculty of Paris at the Sorbon, parish priest of Saint-Supise for thirty five years, towards the end of his life, abbot of Saint Marie de Bernay. Throughout his life he devoted himself to displaying his fervor and magnificence in the worship of the Mother of God. He erected this temple with all the grandeur and majesty one admires today. He conceded the project with no funds other than the Holy Trust. He carries it out thanks to the sovereign's generous piety, yet the preservation of the living temple of Jesus Christ was his foremost and dearest concern. And it goes on and on and on. I'll put a whole the whole thing. On my website, so you could check it out. It might remind you of a cenotaph you have seen if you have visited Notre Dame or seen pictures dedicated to Claude Henri Le Comte de Arcor, created in 1776 by Jean-Baptiste Pigal. Claude Henri Comte de Arcor served as a lieutenant general in the army of Louis XV and died on December 5th, 1769. On July 1st, 1771, the widow Arcor commissioned Pigal to create a theatrical piece titled The Conjugal Reunion. She had very specific instructions for how it would look, which came to her in a dream. At the end of the sarcophagus will be the guardian angel of the Lord. In one hand he holds the torch of their marriage, while the other opens the tomb. Seeing this, the count pulls himself from his tomb and reaches to his wife, who is on her knees in prayer, standing behind in death, holding an hourglass, showing that her time has come. The Count also closely resembles the statue of Voltaire that Pigal created in the Louvre. I love this one, and it's so funny because the her husband that's coming out of the tomb is, you know, older than dirt, and she's this very young, lovely young woman that's now is her time to be taken away. But I guess if I was gonna do one, I'd probably make myself young and lovely as well. Paris is filled with hundreds of sundials and past reminders of how they once calculated the time of the day. The Corps de la Meridienne of the Monet is a sundial that also includes an obelisk and holds the symbol of the zodiac. And the Musee de Monet is the mint, and it is a fantastic place to visit, and very few people go, and it's really, really interesting. Also, within the Palais Royale, a small cannon once fired every day at noon, set off by the sun, hitting a magnifying glass that burned a horsehair, firing the cannon. It was installed in 1786 by Sierra Rousseau to also publicize his watchmaking business. It originally sat on the Meridian line itself, and you could find many of those arigo markers within the entrance to the Palais Royale from the Place Colette, some of the very same ones Tom Hanks stepped over. It was moved to its current location in 1990. The original was stolen in 1998 and never recovered and replaced in 2002 with an exact replica. It still fires on occasion during Heritage Weekend and the anniversary of the liberation on August 25th. According to the website, it will also fire again on Monday, October 19th at noon, and Friday, December 4th. I'll have to go check it out. Another notable example of a sundial is the Dali Sundial. It's you head down Rue Suffo and take a right onto Rue Saint Jacques. The Rue Saint Jacques was once the cardot of Roman Lutitia long before Paris became Paris. The north-south road led to the Chamont de Saint-Jacques and the Santiago de Compostela. At 27 Rue Saint Jacques, look up at the corner. One of the 120 sundials that could be found around Paris resides on this corner. This isn't your normal sundial. It is by the artist Salvador Dali. Placed on November 15, 1966, Dali created it for a friend who owned the shop beneath it. The sundial is a woman's face in the shape of a scallop shell, a nod to the Saint-Jacques de Compostela. Her blue eyes shine beneath her eyebrows, set aflame like the sun. Her hair cascades down, forming the recognizable mustache of her creator. Dolly's signature can be seen in the lower right-hand corner, but don't set your watch by it. The Surrealis artists never designed it to work. It's just for looks. So it's really fascinating, and I can't wait until December to see if this actually works for the winter solstice. And some of the stuff that I read during doing research, one of them said that it doesn't work in the winter because of the buildings outside of it. But I don't know. I'm gonna I'm gonna go check it out for myself. Sansu Ps had two different small books that they have on the subject, and one they have sold for a while. It's just kind of small. And let me tell you, the amount of scientific information just literally made my eyes bleed. But it is, you know, there's a lot of scientific reasonings behind all of this, the access of the earth and everything like that. But uh, you know, if you want, you can go into much deeper on that if you would like. But you there is a kind of just a little almost a pamphlet of a book. And then recently on Heritage Weekend, when I was there, there was another one that was actually just published last year, and it was done by an by a scientist, and that one is in interesting, but but it's funny, both books are very anti-Diminci code, which you know he it's not, as I told you, it's not that same line, you know, and it's a book, it's just a it's just a book and it's just a story. So, you know, that there's a lot of things in that book that people get pretty upset about. And I think on the scheme of it, the the line and which direction it goes in the church is probably the least of the worries for a lot of people with how they feel about that. But you know, I'm gonna have to watch it again now because I probably watch it at least once a month because I love it and because it is filmed inside the Louvre. Sans CP's did not let them film inside, they had to green screen all of it. And it's kind of funny because they added these plants into the into the center of the nave. But, you know, it is on that brass meridian line that Silas takes, takes something and he bashes it into the meridian line because he's looking for the keystone. So, you know, you'll have to watch it again if you haven't seen it. I tell all my clients that they should watch it before they come to Paris just because there's so many great things in it. But be sure, you know, if you want. Some people have let me know that they hate that movie, which is fine to each their own. But next week, I'm really excited for the episode I'm gonna bring you next week. It's about one that I have wanted to do for a very long time, and it is about a gentleman that created a fashion house in Paris, and their big show is tomorrow in Paris. So make sure you check back in next week. If you're coming to Paris and want to do a walking tour on the streets through Paris, we can even find some of those arrogant markers, which is a whole nother episode in and of itself. But make sure you follow along on Instagram, Claudine Blue Blanc Rouge. Also my Substack, the same as well. It's either Claudie Hemingway or Blue Blanc Rouge, my YouTube, all of that kind of stuff. And if you need help planning your trip to Paris, reach out and send me an email and or a form on my website. And I will see you next week. A biento.