Seat of the primate archbishop of England, parts of this cathedral date back to the 12C (choir and crypt), and rebuilt by a Frenchman, Guillaume de Sens, after the fire of 1174. Although it was designed by De Sens, the work was actually carried out by another William, "The Englishman", who complete the choir and designed the plans for the crypt and Trinity Chapel. The Cathedral was completed in the 15C.