Tribe of Reuben in the context of Ten lost tribes

The Twelve Tribes of Israel (Hebrew: שִׁבְטֵי־יִשְׂרָאֵל, romanized: Šīḇṭēy Yīsrāʾēl, lit. 'Staffs of Israel') are described in the Hebrew Bible as being the descendants of Jacob, a Hebrew patriarch who was a son of Isaac and thereby a grandson of Abraham. Jacob, later known as Israel, had a total of twelve sons, from whom each tribe's ancestry and namesake is derived: Reuben, Simeon, Levi, Judah, Dan, Naphtali, Gad, Asher, Issachar, Zebulun, Joseph, and Benjamin. Collectively known as the Israelites, they inhabited a part of Canaan—the Land of Israel—during the Iron Age. Their history, society, culture, and politics feature heavily in the Abrahamic religions, especially Judaism.

In the biblical narrative, after Moses oversaw the Israelites' departure from Egypt, he died and was succeeded by Joshua, who led the conquest of Canaan and subsequently allotted territory for all but the Tribe of Levi, which was instead dedicated 48 cities. This development culminated in the establishment of Israel and Judah, purportedly beginning with a Kingdom of Israel and Judah before splitting into the Kingdom of Israel in the north and the Kingdom of Judah in the south.

The Ten Lost Tribes were those from the Twelve Tribes of Israel that were said to have been exiled from the Kingdom of Israel after it was conquered by the Neo-Assyrian Empire around 720 BCE. They were the following: Reuben, Simeon, Dan, Naphtali, Gad, Asher, Issachar, Zebulun, Manasseh, and Ephraim – all but Judah and Benjamin, both of which were based in the neighbouring Kingdom of Judah, and therefore survived until the Babylonian siege of Jerusalem in 587 BCE. Alongside Judah and Benjamin was part of the Tribe of Levi, which was not allowed land tenure, but received dedicated cities. The exile of Israel's population, known as the Assyrian captivity, was an instance of the long-standing resettlement policy of the Neo-Assyrian Empire implemented in many subjugated territories.

The Jewish historian Josephus wrote that "there are but two tribes in Asia and Europe subject to the Romans, while the ten tribes are beyond Euphrates till now, and are an immense multitude, and not to be estimated by numbers." In the 7th and 8th centuries CE, the return of the Ten Lost Tribes was associated with the concept of the coming of the Hebrew Messiah. Claims of descent from the "lost tribes" have been proposed in relation to many groups, and some Abrahamic religions espouse a messianic view that Israel's tribes will return.

Reuben or Reuven (Hebrew: רְאוּבֵן, Standard Rəʾūven, Tiberian Rŭʾūḇēn) was the first of the six sons of Jacob and Leah (Jacob's oldest son), according to the Book of Genesis. He was the founder of the Israelite Tribe of Reuben.

The Hagrites (also spelled Hagarite or Hagerite, and called Hagarenes, Agarenes, and sons of Agar) were associated with the Ishmaelites mentioned in the Hebrew Bible, the inhabitants of the regions of Jetur, Naphish and Nodab lying east of Gilead. Their name is understood to be related to that of the biblical Hagar. They lived a nomadic, animal-herding lifestyle in sparsely populated land east of the Israelites.

According to First Chronicles 5:18-22, the Reubenites, Gadites, and the half of the tribe of Manasseh in Gilead brought 44,760 to battle with the Hagrites and defeated them. Through the battle, the Reubenites captured the Hagrite land as well as 50,000 camels, 250,000 sheep, 2,000 donkeys. Finally, the Reubenites captured 100,000 Hagrites, men, women and children and held them as captives. According to Theodor Nöldeke, these numbers are "enormously exaggerated".