Maatkare is known from several sources. A statue of the Nile-god - now in the British Museum (BM 8) - was dedicated by his son Shoshenq C, and he lists his parents as Osorkon I and Maatkare. Maatkare is called the King's Daughter of ... Har-Psusennes II, beloved of Amun. On a statue from the Karnak Cachette (Cairo Museum CG 42194), also dedicated by her son Shoshenq, Maatkare has the titles Prophetess of Hathor, Lady of Dendera, God's Mother of Harsomtus, and King's Daughter.
A Karnak inscription on the seventh pylon names a woman called Maatkare, King's Daughter of Psusennes Beloved of Amun, and this is usually though to refer to Maatkare B.