What makes the European Middle Ages religiously decisive is less its beliefs than its institutions, most of which are still standing in some form. Monasticism was organised into orders with written rules, visitation, and international structures, and C. H. Lawrence's survey follows the sequence from Benedictine houses through the reformed Cistercians to the friars, who broke the pattern by living in towns and begging rather than farming an estate. The universities emerged with degrees, faculties, a licence to teach and a corporate identity that could defend itself against bishop and king.
George Makdisi has argued that the college as an endowed teaching institution has a genealogy running through the Islamic world, and the comparison is part of the point: the period was not a single Latin Christian development but four traditions, Latin, Byzantine, Islamic and Jewish, working in contact and in competition across the Mediterranean. Canon law was codified and made marriage, annulment, legitimacy and inheritance matters for church courts. Scholastic theology built a method for arguing doctrine. The cathedrals were financed, designed and built. Every one of those is an arrangement rather than an idea, and arrangements outlive the arguments that produced them.