Bahrain was referred to by the Greeks as Tylos. It was the centre of pearl trading, when "Nearchus" came to discover it serving under Alexander the Great. From the 6th to 3rd century BC Bahrain was in the Persian Empire. The Greek historian, Theophrastus, states that much of the islands were covered in cotton trees. Tylos was famous for selling walking canes that were carried in Babylon. Ares was worshipped by the ancient Baharna and the Greek colonists.