Cyrene dates back to the first half of the 7th century BC, when settlers arrived from the Greek island of Thera (now known as Santorini) and established themselves. On the death of Alexander the Great, Cyrenaica passed into the hands of the Egyptian ruler, Ptolemy, and by 75BC had become part of the Roman Empire. Unrest grew and various revolts flared up and were suppressed, the most serious being quashed by the Emperor Trajan in AD115. Later the Emperor Hadrian made some attempts at reconstructing the now declining city, but with no real success.