The Knights Hospitaller built their Castle near the site and scavenged material from the Mausoleum. Sir Thomas Docwra was one time captain of the castle. In 1522 when faced by attack from Sultan Suleiman the Grand Master of the Hospitallers ordered the castle to be repaired. The hopitallers broke open the Mausoleum, finding all sorts of elaboratedly adorned marble and carvings which they admired and then destroyed using the debris as building material. They discovered the sarcophagus of Mausolus, but this was stolen during the night. The Knights Hospitaller were soon defeated and driven from Budrum. Some decorative slabs have been found in the ruins of the castle and one slab has turned up in Genoa.
In 1846 Lord Stratford de Redeliffe, the British Ambassador to Constantinople obtained permission to take twelve slabs showing combat between Greeks and Amazons. Sir Charles Newton conducted excavations and removed a number of stone lions in 1856. These are all to be found at the British Museum.