The first reference to a house on the present site was in 1332 when the Itinerent Justices visited the Island and on at least one occasion sat at the Manor. The next reference was in 1560 when Clement Messervy married Collette Nicolle, whose brother was the Bailiff, Hoste Nicolle. In 1631, in the memoirs of Benjamin La Cloche, reference is made to alterations he was making and there is good reason to believe that it was he who panelled the Great Hall using oak chests which to this day, nearly 400 years on, are still in position in what is now the Oak Room Restaurant.
Sadly, there are very few historical facts recorded on the history of the Manor, but from what is known it can be reasonably assumed that the original front, which runs East to West, dates back to the 16th Century. The main entrance today, with its fine and elaborate arch, is assumed to date back to 1550, although there is good reason to believe it may be earlier. Longueville Manor had its own chapel. Dedicated to St. Thomas, the chapel is referred to in the Assize Roll of 1309. The small granite house just north east of the Tower is often referred to as the Priest's House or Presbytere and has many features associated with the 16th Century.
For the most part, through the ages, the Manor lacked care and attention and on many occasions fell into a sad state of repair. There were exceptions such as Benjamin La Cloche in the 17th Century and the Rev. W.B. Bateman in the 19th Century.
During the Second World War, whilst the Island was occupied by the Germans, the Manor was used as Officers' quarters. Between the beginning of the Occupation of Jersey in May 1940 and the purchase by the Lewis family in 1948, the Manor fell into a state of neglect and disrepair.