The largest and oldest basilica churches in Egypt were at Pbow, a coenobitic monastery established by Pachomius the Great in 330. The 4th century basilica was replaced by a large 5th century building (36 × 72 m) with five aisles and internal colonnades of pink granite columns and paved with limestone. This monastery was the administrative centre of the Pachomian order where the monks would gather twice annually and whose library may have produced many surviving manuscripts of biblical, Gnostic, and other texts in Greek and Coptic. In North Africa, late antique basilicas were often built on a doubled plan. In the 5th century, basilicas with two apses, multiple aisles, and doubled churches were common, including examples respectively at Sufetula, Tipasa, and Djémila. Generally, North African basilica churches' altars were in the nave and the main building medium was "opus africanum" of local stone, and "spolia" was infrequently used.