Qasr Libya or Qasr Lebia (, lit. 'Lebia Castle', Lebia/Libya being a corruption of the ancient nameàOlbia) is a small town in northern Libya about northwest of Bayda. In ancient times, it was a Roman / Byzantine town called Olbia and Theodorias, the ruins of which were excavated in the 1950s. The town contains a museum with fifty Byzantine mosaics. It is on the cross-roads between the eastwards MarjâÂÂBayda main road, and the southwards Qasr LibyaâÂÂMarawa road.