Cathedrals are the seats of Catholic bishops (catedra = seat in Latin).
The bishop's role is to administer their diocese and teach their congregations.
As a majority of the medieval population was illiterate, cathedral artworks were used as opportunities to drive messages home.
The facades often had this purpose - referred to as a "Poor Man's Bible".
High above the doors is a gallery of stone figures representing the descendants of Abraham in the Christian faith - the 28 kings of Judah.
Fun fact : Revolutionaries mistakenly thought they were French kings so they were tore them down and beheaded them.
The portal above the main door represents the Last Judgement - when God judges souls, sending some to heaven and others to hell.
Jesus is at the top, presiding over the scene, with angels on both side holding the holy cross, nails and lance and the Virgin Mary and Saint John praying for him to show mercy.
At the bottom, souls are being resuscitated by two angels with trumpets.
The archangel Michael weighs souls on a set of scales - with a demon trying to tip the scales to his side.
The saved are on the left - pious and relaxed - and the damned are on the right - led off by demons, scared and in chains.
A king, a bishop and a rich man are seen being crushed by a demon.
This is hugely important as the message is clear - the Last Judgement applies to all, whether rich or poor, royalty or clergy.
Hundreds of spectators are represented watching the scene - including Abraham with 3 hidden souls in his tunic.