The gatehouse served as the main entrance into a complex of buildings based around a quadrangle. The gatehouse was built from 1459-1469 by John Carpenter, the Bishop of Bath and Wells as part of his ambitious plan to extend the earlier college.
After the Reformation, the College buildings were converted into a residence by Sir Ralph Sadler, but that residence was slighted by Prince Rupert in the Civil War to prevent it being used by Parliamentarian troops.
In the late 18th century a Georgian house was built beside the gatehouse, and the only surviving parts of the original medieval college buildings are a pair of round towers and a section of wall visible on Trym Road and College Road.
The gateway stands 4 stories high, and the arch is vaulted in two bays. The gatehouse is topped with a parapet and corner turrets.
The gatehouse passed to the National Trust in 1907 but is leased to Holy Trinity Church for use as a meeting place. Regular opening hours, but arrangement must be made in advance to collect the key from the Parish Office nearby.