A book of law and oaths
This book contains the Charters of King James I and Alphonse II of Valencia and is signed by the notary Boronat de Pera, who directed the elaboration under the mandate of King Alphonse (which conferred law status to the book). In years after 1240 the aspirations of the "costum" depended on the King’s willingness, who had granted it. For this the city and some towns attempted to obtain the irrevocability of Valencian law on behalf of the King, the definite constitution of the Kingdom as Autonomous State.
This took place in April 1261, in which evidence is shown of the celebration of the first Valencian "Corts", in which king James swore in the "Furs" and the "Costumes" of Valencia, and stated that, just as he had sworn and confirmed the charters and the customs, his successor should also do so before the "Cort General", at the beginning of their reign.