Insula XVII lies within the Gorhambury estate, immediately opposite the theatre and on the east side of the modern drive, which here almost coincides with the underlying Watling Street. It was while excavation of the theatre was in progress in 1934 that part of this area was opened up, in the process of locating the foundations of the triumphal arch which had spanned the Roman street at this point. The frontage of an apparently imposing building, running parallel to Watling Street, was then uncovered, but, though the exposed walls were planned by Mr. A. W. G. Lowther, A.R.I.B.A., F.S.A., no further work was undertaken in this area at that time and the masonry was covered in again. As the area in question lies close to the civic centre of the Roman city, now buried beneath St. Michael's churchyard and vicarage garden, and as already the theatre and a Romano-Celtic temple had been found in Insula XVI immediately to the west, it seemed likely that this new building might likewise be monumental in character and would repay further investigation. It was also hoped that excavation here, within the compass of the early Roman city might throw more light both on the earliest and on the latest occupation of the site. The Earl of Verulam was therefore approached and I would like at this point to record the thanks of the Verulamium Excavation Committee for generous permission to undertake the work.