they formed a unified alliance to fight against Joshua and Israel.

And from there he went up against the inhabitants of Debir (the former name of Debir [was] Kiriath Sepher).

The border changed course [from there] and turned around on the western side southward, from the hill that lies to the south opposite Beth-horon; it ended at Kiriath-baal (that is, Kiriath-jearim), a city of [the tribe of] the sons of Judah. This formed the western side [of Benjamin’s territory].

The Jordan formed the border on the east side.

This was the inheritance of Benjamin’s descendants, by their clans, according to its surrounding borders.

And Joshua said unto all the people, Thus says the LORD God of Israel, Your fathers dwelt on the other side of the River in former times, even Terah, the father of Abraham, and the father of Nahor: and they served other gods.