St. Denis Abbey
The Abbey of St. Denis was a royal abbey, site of both the coronations and burials of French kings. The church was founded by Dagobert I (circa 630), and in the crypt some arches remain from that structure. Consecrated before Charlemagne, in the twelfth century the abbey offered refuge to the philosopher Abelard after he was castrated for his relationship with Heloise. Later, Jeanne d'Arc offered her sword and armor upon the altar of this church, and Henri IV abjured Protestantism there. The abbey school trained princes and the most important aristocrats, and it was there that the future Abbot Suger was educated alongside the future King Louis VI.
As abbot, Suger's two aims were to strengthen the Capetian crown and aggrandize the abbey. He served as regent from 1147-1149 when Louis VII went on the Second Crusade, and did so well at controlling the turbulent vassals that the king bestowed upon him the title of "Father of the Country". Abbot Suger used his connections at court to assist in raising funds for a new abbey church, which was the first example of true Gothic architecture. The ribbed vaults and flying buttresses allowed more open space for stained glass windows, which Suger used (along with precious stones) to express the doctrine of divine light, believing that "the dull mind rises to truth through that [refracted light] which is material".(De Administratione, XXVII)
Medieval monasteries, in addition to housing monks dedicated in service to God, were self-supporting business enterprises that offered valuable services to the surrounding countryside. Food surplus was traded locally, abbey flocks were the foundation of the wool industry, and workshops produced other items for sale or trade at the annual fairs. Abbeys offered lodging and a free meal (accompanied by scripture reading) to poor travellers, and wealthier travelers' donations could procure finer accomodations and perhaps even a visit with the abbot. Until the rise of the universities, monasteries were also the seat of most scholarly and medical knowledge, and provided education to the wealthy, among whom it was tradition to dedicate the third son to God (as an oblate).
In the game, the Abbey of St. Denis' layout is based on the St. Gall Plan, which showed the layout of an ideal monastery. No actual sites follow this plan exactly, but the modern Abbey of St. Denis has been reduced to just the abbey church (and even that exists only partially in its twelfth century form), so the St. Gall Plan was used in lieu of a real world layout.