There is evidence of an early settlement in Tripoli that dates back as early as 1400 BC. In the 9th century BC, the Phoenicians established a trading station in Tripoli and later, under Persian rule, the city became the center of a confederation of the Phoenician city states of Sidon, Tyre, and Arados Island. Under Hellenistic rule, Tripoli was used as a naval shipyard and the city enjoyed a period of autonomy. It came under Roman rule around 64 BC. In 551 AD, an earthquake and tidal wave destroyed the Byzantine city of Tripoli along with other Mediterranean coastal cities.During Umayyad rule, Tripoli became a commercial and shipbuilding center. It achieved semi-independence under Fatimid rule, when it developed into a center of learning. The Crusaders laid siege to the city at the beginning of the 12th century and were able finally to enter it in 1109. This caused extensive destruction, including the burning of Tripoli's famous library, Dar al-Ilm (House of Knowledge), with its thousands of volumes. During the Crusaders' rule the city became the capital of the County of Tripoli. In 1289, it fell to the Mamluks and the old port part of the city was destroyed. A new inland city was then built near the old castle. During Ottoman rule from 1516 to 1918, it retained its prosperity and commercial importance. Tripoli and all of Lebanon was under French mandate from 1920 until 1943, when Lebanon achieved independence.