This was the capital city of the Nabateans, who first appeared in history in 312 B.C. The Nabateans were of Arabic origin, though their ancestry is uncertain. They occupied the old land of Edom and made Petra their capital. Petra lay in an impressive valley about 1,000 yards (914.4 meters) wide among the mountains of western Edom, some 60 miles (96.5 kilometers) north of Aqaba. The only access to the valley is through a narrow gorge called the Siq. Massive cliffs of reddish sandstone arise on all sides. Today, ruins of many temples, houses, tombs, and other structures hewn out of the reddish sandstone remain. A Roman basilica and theater are still to be seen. The place continued through Roman times and later had a Christian church and a bishop. It fell into ruins during the days of the Muslim conquest in the seventh century A.D.