The Statute of Westminster, the first - 1275

Edward the 1st is just back from Crusade and he has laws to pass.

The Statute of Westminster  dates from 1275. 

Why was it passed, what was it's purpose and  what parts of it are still in force?

These be the Acts of King Edward, Son to King Henry, made at Westminster at his first Parliament general after his Coronation, on the Monday of Easter Utas, the Third Year of his Reign, by his Council and by the assent of Archbishops, Bishops, Abbots, Priors, Earls, Barons, and [all] the Commonalty of the Realm, being thither summoned: Because our Lord the King had great zeal and desire to redress the State of the Realm in such Things as required Amendment for the common profit of Holy Church, and of the Realm: And because the State of the Holy Church had been evil kept, and the Prelates and Religious Persons of the Land grieved many ways, and the People otherwise intreated than they ought to be, and the Peace less kept, and the Laws less used, and the Offenders less punished, than they ought to be, by reason whereof the People [of the Land] feared the less to offend; the King hath ordained and established these Acts underwritten, which he intendeth to be necessary and profitable unto the whole Realm.

• The Statute of Westminster, The First - 1275

I would like to credit the Conet Project for the weird intro music: https://freemusicarchive.org/music/The_Conet_Project/