The Temple of Claudius, Insula 22.
The Temple was founded in the AD 50's, although there is some debate as to whether it would have been built before or after the death of Claudius in AD 54. The temple served as the centre of the Imperial cult in the province and dominated the eastern half of the city. The temple was surrounded by a large precinct and may have been served by administrative buildings situated in Insula 30. Much of the vaulted podium base of the temple has been preserved below Colchester castle, although none of the superstructure has survived. The base provides a clear indication of the scale of the building and based on the principles of Roman architect Vitrvius the building would have been over 20m high. The podium measures 32 x 23.5m. For Precinct see MCC1544.

Trenches were cut through the wall of the temple podium by P.G. Laver in 1922.<1> In 1925 the north west angle of the temple podium was opened.<2>

During the period between 1931 and 1933 Dr. P. G. Laver made several investigations into the Castle Keep. In 1931 a north-south section was cut 'with great difficulty' in the small prison. It was made through a limited gap in the Norman tile floor.<3> The exact dimensions of this excavation are unknown. In 1932 Trenches cut by Laver <4> included one at right angles to the east wall of the keep, immediately south of the existing doorway. This revealed a drain-pipe and robbing of the Roman work. Two other trenches were cut up to the west face of the remaining Norman partition wall and revealed the temple podium and in 1933 a long east-west section was excavated through the sub-crypt 'small prison'. Again the dimensions of this excavation are unknown.<5>

Investigations were carried out of the remains of the temple podium and overlying deposits beneath Colchester Castle, ahead of the insertion of a lift shaft. An area of 2.4 x 2.3m was exposed revealing the podium at a depth of 3.15m from the castle floor. No features of Norman or later medieval date were observed. The total area examined covered 3 x 2.5m and also revealed post medieval stone robbing activities as well as post holes and a trench attributable to the time of Charles Grey's ownership.<6>

Samples of the mortar from the foundations of the temple of Claudius were examined and reported on by the research department of the Cement and Concrete Association. A report was produced by H. M. Carter of C.A.G.<7>