In the Biblical account, Leah's status as the first wife of Jacob, is regarded by biblical scholars as indicating that the authors saw the tribe of Issachar as being one of the original Israelite groups; however, this may have been the result of a typographic error, as the names of Issachar and Naphtali appear to have changed places elsewhere in the text, and the birth narrative of Issachar and Naphtali is regarded by textual scholars as having been spliced together from its sources in a manner which has highly corrupted the narrative. A number of scholars think that the tribe of Issachar actually originated as the Shekelesh group of Sea Peoples - the name Shekelesh can be decomposed as men of the Shekel in Hebrew, a meaning synonymous with man of hire (ish sakar); scholars believe that the memory of such non-Israelite origin would have led to the Torah's authors having given Issachar a handmaiden as a matriarch.
In classical rabbinical literature, it is stated that Issachar was born on the fourth of Ab, and lived 122 years. According to the midrashic Book of Jasher, Issachar married Aridah, the younger daughter of Jobab, a son of Joktan; the Torah states that Issachar had four sons, who were born in Canaan and migrated with him to Egypt, with their descendants remaining there until the Exodus. The midrashic Book of Jasher portrays Issachar as somewhat cowardly, or at least pragmatic, with him taking a feeble part in military campaigns involving his brothers, and generally residing in strongly fortified cities, opening the gates whenever challenged.
The Talmud argues that Issachar's description in the Blessing of Jacob - Issachar is a strong ass lying down between the sheepfolds: and he saw that settled life was good, and the land was pleasant; he put his shoulder to the burden, and became a slave under forced labour - is a reference to the religious scholarship of the tribe of Issachar, though scholars feel that it may more simply be a literal interpretation of Issachar's name, and the justification for the tribe of Issachar being a tributary to the Canaanites.