In the early 16th century, the college's St. Antony's and Dudley exhibitioners were lodged in St Mary Hall and Bedel Hall, and around this time the two halls were united. St. Mary Hall subsequently developed into an independent entity, and in 1545, on the order the
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.
In 1552, there were 18 members of St. Mary Hall, excluding the Principal. The
Principals of St Mary Hall continued to be
fellows of Oriel until 1656. 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.
The Hall was effectively the property of its Principal, who was also Vicar of St Mary's Church. The last Principal,
Drummond Percy Chase, who had been appointed in 1857, created an agreement with Oriel as a consequence of which the Hall became the property of Oriel on his death, which subsequently occurred in 1902, when according to the agreement, the Hall was incorporated into Oriel College. Some agreements created when St. Mary Hall were a separate organisation continue to exist: for example, the
benefice of the Vicar of St Mary's Church includes dining rights at Oriel.
The present St. Mary's Quad, or 'third quadrangle', of Oriel occupies three ranges of the former buildings of the St. Mary Hall. 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.
^Salter H. E. and Lobel, M. D. (editors), "St Mary Hall", A History of the County of Oxford: Volume 3: The University of Oxford (1954) pp. 129–131, Oxford University Press VCH series,
^Barbara Harlow, Mia Carter, Archives of Empire: Volume 2. The Scramble for Africa, p. 545