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Notes in italics from Hampshire and the Isle of Wight by Nikolaus Pevsner and David Lloyd (1967)
Yale University Press, New Haven and London.

First built c.1135 by Bishop Henry of Blois on the site of a cemetery. Reconstruction on an ambitious scale seems to have taken place c.1160-80. There were various alterations in the next two centuries, and extensive rebuilding in the C15, especially during the episcopate of Bishop Langton (1493-1501). The palace was still occupied by bishops in the early C17, but it was damaged in the Civil War and subsequently allowed to fall into complete ruin. ... The palace was contained in a rectangular site surrounded by a moat, stretches of which are still visible, partly filled with water, especially on the W side. ... The principal palace buildings were along the W and S sides of the rectangle, and much remains of the W range, facing, over the moat, the present main road to Winchester.

The Great Hall occupies the centre part of the range; the hall of c.1160-80 was built at first floor level on an undercroft, but in the late C15 the undercroft was removed, the space it had occupied partly filled with earth, and a new hall floor constructed on a level between that of the previous floor and the original ground level. Remains of a C12 arcade in the S wall indicate the level of the previous floor. The W wall of the hall substantially remains, with the openings and part of the stonework of tall transomed two-light Perp windows.

Immediately to the S (of the hall) is a room retaining a C12 window in its W wall. This connect with the tower in the SW corner of the palace, essentially of c.1160-80 and remaining to its full height of three storeys on its S and W sides. It contains the remains of C12 and C15 windows as well as of fireplaces. ... These were the bishop's private apartments. 

At the S end of the S range are the foundations and crypt of the apsidal chapel, a survival of the first palace of Bishop de Blois ...

Detached from the ruins of the main building, to the NE, is a complete shell of the East Range, an austere early C14 two-storey building, altered in the late C16, with small square-headed window openings and plain doorways. This was the bakehouse and brewhouse, built 1378-81 by Wykeham and heightened 1439-41 by Beaufort.

This brick and stone building was built by Beaufort 1438-43 and was part of a long range along the north side built to house guests. Original diapered brickwork can be seen on the end in the second picture; it is some of the earliest in the county. The building was adapted as a farmhouse in the late 17th century. It has now been restored inside and includes a display of carved stones from the palace site. The last picture shows a corbel bust of Cardinal Beaufort. It is believed that it supported the main arch over the entrance gate to the inner court.