BEIRUT, Lebanon (AP) _ Under the ruins of a landmark cinema ravaged by the civil war, archaeologists have unearthed remnants of a castle built in Beirut by 12th century Crusaders.

While Lebanon _ especially Beirut _ is rich in archaeological finds from the Canaanite, Phoenician and Roman eras, the discovery of a Crusader building by a team of American University of Beirut archaeologists was a first for the Lebanese capital's downtown.

The discovery last week was only possible after much of the downtown had been razed to make way for reconstruction of the city center from the devastation of the 1975-90 war.

Hints of the castle's existence had circulated for years. Leila Badr, head of the archaeological team, said a French historian had written about a Crusader castle built near the seafront in Beirut to protect the Lebanese coastline.

Marble pillars with Roman etchings were first found by the team under 30 feet of soil _ the first solid proof of the castle's existence, she said.

``The Crusaders have used old Roman pillars in the building of their castles. Since we discovered the pillars, we realized the castle definitely existed,'' Ms. Badr told An-Nahar newspaper.

The main wall of the castle was later unearthed from under the Rivoli cinema, which was dynamited and bulldozed last summer.

The Crusades were a series of wars undertaken by European Christians between the 11th and 14th centuries to reconquer the Holy Land from its Muslim rulers. They took Beirut in 1110 and built castles on Lebanon's mountains and the coastline to defend against attacks.