late Hellenistic period, the area had a mixed population of Jews, Greeks, Nabataeans, other Arabs, and descendants of Ammonites. One of the best surviving structures from that period is Qasr al-Abd, a Hellenistic palace built by the Jewish Tobiad family, close to the village of Iraq al-Amir.The Nabataeans, nomadic Arabs based south of Edom, managed to establish an independent kingdom in the southern parts of Jordan in 169 BC by exploiting the struggle between the two Greek powers. The Jewish Hasmonean Kingdom also took advantage of the growing geopolitical vacuum, seizing the area east of the Jordan River valley. The Nabataean Kingdom gradually expanded to control much of the trade routes of the region, and it stretched south along the Red Sea coast into the Hejaz desert, up to as far north as Damascus, which it controlled for a short period (85–71) BC. The Nabataeans massed a fortune from their control of the trade routes, often drawing the envy of their neighbours. Petra, Nabataea's barren capital, flourished in the 1st century AD, driven by its extensive water irrigation systems and agriculture. The Nabataeans were also talented stone carvers, building their most elaborate structure, Al-Khazneh, in the first century AD. It is believed to be the mausoleum of the Arab Nabataean King Aretas IV. Roman legions under Pompey conquered much of the Levant in 63 BC, inaugurating a period of Roman rule that lasted four centuries. The eastern side of the Jordan River valley, known then as Perea, was part of the Herodian Kingdom of Judea, a vassal state of the Roman Empire. During that time period, the area became the setting for some important events in Christianity, including the Baptism of Jesus. In 106 AD, Emperor Trajan annexed the Nabataean Kingdom unopposed, and rebuilt the King's Highway which became known as the Via Traiana Nova road. The Romans gave the Greek cities of Transjordan–Philadelphia (Amman), Gerasa (Jerash), Gedara (Umm Quays), Pella (Tabaqat Fahl) and Arbila (Irbid)–and other Hellenistic cities in Palestine and southern Syria, a level of autonomy by forming the Decapolis, a ten-city league. Jerash is one of the best preserved Roman cities in the East; it was even visited by Emperor Hadrian during his journey to Syria Palaestina. In 324 AD, the Roman Empire split, and the Eastern Roman Empire–later known as the Byzantine Empire–continued to control or influence the region until 636 AD. Christianity had become legal