In 1066 there were only two monasteries in the city of London (Holy Trinity Priory (Aldgate) and St Martin's-le-Grand), and two nearby (at Westminster and Bermondsey). Many more were established in the 1100s and 1200s, including nunneries such as St Mary's Clerkenwell. The Knights Templar and the Knights of St John also had London bases.
Hospitals were founded around the city, some like St Giles in the Fields providing refuge for sufferers from leprosy. In the mid 1200s groups of friars including the Dominican or Black Friars settled in London and built great preaching churches.
There have been excavations on many of these monastic sites, as at Merton Priory and the great hospital of St Mary Spital in Spitalfields.