Bethamnaram trans Iordanem, quam aedificavit tribus Gad. Est hodieque villa Bethnamaris in quinto a Liviade miliario contra aquilonem.
(Jerome 45:21-23)

Eusebius, Onomasticon 44:16-18 (ca. 295 A.D.); Jerome 45:21-23 (ca. 390 A.D.)
Bethnamran (Num 32:36) beyond the Jordan, which the tribe of Gad built. And today there is a village (called) Bethnambris (Bethnamaris) at the fifth milestone from Livias to the north.

BIBLICAL BACKGROUND

Num. 32:1-5.34-36 The allocation of Transjordania
Now the Reubenites and the Gadites owned a very great number of cattle. When they saw that the land of Jazer and the land of Gilead was a good place for cattle, the Gadites and the Reubenites came and spoke to Moses, to Eleazar the priest, and to the leaders of the congregation, saying, "Ataroth, Dibon, Jazer, Nimrah, Heshbon, Elealeh, Sebam, Nebo, and Beon - the land that the Lord subdued before the congregation of Israel - is a land for cattle; and your servants have cattle." They continued, "If we have found favor in your sight, let this land be given to your servants for a possession; do not make us cross the Jordan." ... And the Gadites rebuilt Dibon, Ataroth, Aroer, Atroth-shophan, Jazer, Jogbehah, Beth-nimrah, and Beth-haran, fortified cities, and folds for sheep.

Josh. 13:24-28 The lot of the tribe of Gad
Moses gave an inheritance also to the tribe of the Gadites, according to their families. Their territory was Jazer, and all the towns of Gilead, and half the land of the Ammonites, to Aroer, which is east of Rabbah, and from Heshbon to Ramath-mizpeh and Betonim, and from Mahanaim to the territory of Debir, and in the valley Beth-haram, Beth-nimrah, Succoth, and Zaphon, the rest of the kingdom of King Sihon of Heshbon, the Jordan and its banks, as far as the lower end of the Sea of Chinnereth, eastward beyond the Jordan. This is the inheritance of the Gadites according to their clans, with their towns and villages.

MORE ANCIENT SOURCES

Josephus, War 4.7.4 (1st cent. A.D.)
(419) And now Vespasian sent Placidus against those that had fled from Gadara, with five hundred horsemen, and three thousand footmen, while he returned himself to Cesarea, with the rest of the army. (420) But as soon as these fugitives saw the horsemen that pursued them just upon their backs, and before they came to a close fight, they ran together to a certain village, which was called Bethennabris, (421) where finding a great multitude of young men, and arming them, partly by their own consent and partly by force, they rashly and suddenly assaulted Placidus and the troops that were with him.