The first king that Moses and the Israelites defeated was an Amorite, King Sihon of Heshbon. The southern border of his kingdom ran down the middle of the Arnon River gorge, taking in the town of Aroer on the northern edge of the gorge. The Jabbok River separated Sihon's kingdom from the Ammonites on the east. Then the Jabbok turned west and became his northern border, so his kingdom included the southern half of the region of Gilead.
The Amorite King Sihon had lived in Heshbon and had ruled the towns in the flatlands. Now Heshbon belonged to Reuben, and so did the following towns in the flatlands: Dibon, Bamoth-Baal, Beth-Baal-Meon, Jahaz, Kedemoth, Mephaath, Kiriathaim, Sibmah, Zereth-Shahar on the hill in the valley, Beth-Peor, Slopes of Mount Pisgah, and Beth-Jeshimoth. Moses defeated Sihon and killed him and the Midianite chiefs who ruled parts of his kingdom for him. Their names were Evi, Rekem, Zur, Hur, and Reba.