St. Mary Hall subsequently developed into an independent entity, and in 1545, on the order the Visitor, Bishop Longland of Lincoln, the door between St Mary Hall and Oriel was blocked.

The Hall subsequently employed its own lecturers, and the intake of St Mary's was periodically more than that of Oriel.

By 1875, the size of St.Mary Hall's undergraduate body had risen to 60, a large number for one of the University's colleges at that time.

[3] The Hall was effectively the property of its Principal, who was also Vicar of St Mary's Church.

The Principal's house was demolished for the construction of the Rhodes Building, which was designed by Basil Champneys, and which was completed in 1911.