Usermaatre Setepenamun Osorkon II was a pharaoh of the Twenty-second Dynasty of Ancient Egypt and the son of Takelot I and Queen Kapes. He ruled Egypt around 872 BC to 837 BC from Tanis, the capital of this Dynasty. After succeeding his father, he was faced with the competing rule of his cousin, king Harsiese A, who controlled both Thebes and the Western Oasis of Egypt. Osorkon feared the serious challenge posed by Harsiese's kingship to his authority but, when Harsiese conveniently died in 860 BC, Osorkon II ensured that this problem would not recur by appointing his own son Nimlot C as the next High Priest of Amun at Thebes. This consolidated the pharaoh's authority over Upper Egypt and meant that Osorkon II ruled over a united Egypt. Osorkon II's reign would be a time of large scale monumental building and prosperity for Egypt
According to a recent paper by Karl Jansen-Winkeln, king Harsiese A, and his son [..du] were only ordinary Priests of Amun, rather than High Priests of Amun, as was previously assumed. The inscription on the Koptos lid for [..du], Harsiese A's son, never once gives him the title of High Priest. demonstrates that the High Priest Harsiese who served is attested in statue CGC 42225 – which mentions this High Priest and is dated explicitly under Osorkon II – was, in fact, Harsiese B. The High Priest Harsiese B served Osorkon II in his final 3 years. This statue was dedicated by the Letter Writer to Pharaoh Hor IX, who was one of the most powerful men in his time. However, Hor IX almost certainly lived during the end of Osorkon II's reign since he features on Temple J in Karnak which was built late in this Pharaoh's reign, along with the serving High Priest Takelot F(the son of the High Priest Nimlot C and therefore, Osorkon II's grandson). Hor IX later served under both Shoshenq III, Pedubast I and Shoshenq VI. This means that the High Priest Harsiese mentioned on statue CGC 42225 must be the second Harsiese: Harsiese B.
Despite his astuteness in dealings with matters at home, Osorkon II was forced to be more aggressive on the international scene. The growing power of Assyria meant the latter's increased meddling in the affairs of Israel and Syria – territories well within Egypt's sphere of influence. In 853 BC, Osorkon's forces, in a coalition with those of Israel and Byblos, fought the army of Shalmaneser III at the Battle of Qarqar to a standstill thereby halting Assyrian expansion in Canaan, for a brief while.
Osorkon II devoted considerable resources into his building projects by adding to the temple of Bastet at Bubastis which featured a substantial new hall decorated with scenes depicting his Sed festival and images of his Queen Karomama. Mutemhat was another of his wives. Monumental construction was also performed at Thebes, Memphis, Tanis and Leontopolis. Osorkon II also built Temple J at Karnak during the final years of his reign, which was decorated by his then serving High Priest Takelot F(the future Takelot II). Takelot F was the son of the deceased High Priest Nimlot C and, thus, Osorkon II's grandson. Osorkon II was the last great Twenty-second Dynasty king of Tanis who ruled Egypt from the Delta to Upper Egypt because his successor, Shoshenq III lost effectively control of Middle and Upper Egypt in his 8th Year with the emergence of king Pedubast I at Thebes.
Recently, it has been demonstrated that Nile Quay Text No.14 (dated to Year 29 of an Usimare Setepenamun) belongs to Osorkon II on palaeographical grounds. This finding suggests that Osorkon II likely did celebrate his first Heb Sed in his 30th Year as was traditionally the case with other Libyan era Pharaohs such as Shoshenq III and Shoshenq V. In addition, a Year 22 stela from his reign preserves no mention of any Heb Sed celebrations in this year as would be expected, (see Von Beckerath).
While Osorkon II's precise reign length is unknown, some Egyptologists such as Jürgen von Beckerath – in his 1997 book Chronology of the Egyptian Pharaohs – and Aidan Dodson have suggested a range of between 38 to 39 years. However, these much higher figures are not verified by the current monumental evidence. Gerard Broekman gives Osorkon II a slightly shorter reign of 34 Years.
Osorkon II appointed his third son Hornakht as the chief priest of Amun at Tanis to strengthen his authority in Lower Egypt; however, this was clearly a political move since Hornakht died prematurely before the age of 10. In this period of Egypt's history, religious and political power were at their most inseparable.
The English Egyptologist Aidan Dodson in his book, The Canopic Equipment of the Kings of Egypt, observes that Shoshenq III built "a dividing wall, with a double scene showing Osorkon II" and himself "each adoring an unnamed deity" in the antechamber of Osorkon II's tomb. Dodson concludes that while one may argue Shoshenq III erected the wall to hide Osorkon II's sarcophagus, it made no sense for Shoshenq to create such an elaborate relief if Takelot II had really intervened between him and Osorkon II at Tanis for 25 years unless Shoshenq III was Osorkon II's immediate successor. Shoshenq III must, hence, have wished to associate himself with his predecessor – Osorkon II. Consequently, the case for establishing Takelot II as a Twenty-second Dynasty king and successor to Osorkon II disappears, as Dodson writes.