Akheperre Setepenre Osorkon the Elder is the fifth king of the twenty-first dynasty of Egypt and was the first pharaoh of Libyan extraction in Egypt.
He is also sometimes known as "Osochor," following Manetho's Aegyptiaca.
Osorkon the Elder was the son of Shoshenq, the Great Chief of the Ma by the latter's wife 'Mehtenweskhet who is given the prestigious title of 'King's Mother' in a document.
Osochor was the brother of Nimlot A, the Great Chief of the Ma, and Tentshepeh A the daughter of the Great Chief of the Ma and, thus, an uncle of Shoshenq I, founder of the Twenty-second Dynasty.
His existence was doubted by most scholars until Eric Young established in 1963 that the induction of a temple priest named Nespaneferhor in Year 2 I Shemu day 20 under a certain king named Akheperre Setepenre—in fragment 3B, line 1-3 of the Karnak Priest Annals —occurred one generation prior to the induction of Hori, Nespaneferhor's son in Year 17 of Siamun, which is also recorded in the same annals.
Young argued that this king Akheperre Setepenre was the unknown Osochor.
This hypothesis was not fully accepted by all Egyptologists at that time, but in a 1976-1977 paper, Jean Yoyotte noted that a Libyan king named Osorkon was the son of Shoshenq A by the Lady Mehtenweshkhet, with Mehtenweshkhet being explicitly titled the "King's Mother" in a certain genealogical document.
Since none of the other kings named Osorkon had a mother named Mehtenweshkhet, it was conclusively established that Akheperre Setepenre was indeed Manetho's Osochor, whose mother was Mehtenweshkhet.
The Lady Mehtenweshet A was also the mother of Nimlot A, Great Chief of the Meshwesh and, thus, Shoshenq I's grandmother.
