sentences:  Part of the existing building is dated to 1419.In his 1882 publication, local historian Octavius Morgan provides a description of three carved stones, showing symbols of the Holy Trinity, which once formed part of a grand gateway to the palace, but by then deposited by Lord Tredegar at the museum at Caerleon, dating from the time of Bishop John de la Zouch who held the See between 1408 and 1423.Most of the remaining buildings, however, date from the 16th century.