sentences:  Atop the mound are two medieval chapels, one from the 12th Century and the other from the 16th Century.This building complex has been altered a great deal through its history–including being engulfed for a period by the "Prince’s Tower".Construction of this tower was started in 1792 by Philippe d'Auvergne, the nephew of Major-General James d'Auvergne, who erected a signal station on the tower for use in his work for the British Secret Intelligence Service.