Ancient Greek city, western Anatolia. Located in modern Turkey on a peninsula in the Aegean Sea, it became the capital of Caria (c. 370 BC) under the Persian satrap Mausolus, who built a great wall, public buildings, and a secret dockyard and canal. His widow erected (c. 350 BC) a great tomb (the Mausoleum) in his memory. It was one of the Seven Wonders of the ancient world, and its remains are now in the British Museum. Halicarnassus was the birthplace of the Greek historian Herodotus. It came under Roman rule in 129 BC, and in early Christian times was a bishopric. The ruins of the castle of the Knights of St. John, founded c. AD 1400, dominate the ancient site.