At-Tabarī
Ibrahim ruled for two months in 744 before he abdicated, and went into hiding out of fear of his political opponents. The shortness of this time and his incomplete acceptance led Muhammad ibn Jarir al-Tabari to state that he did not succeed in becoming caliph (v. 26, p. 247). However, al-Tabari (p. 13) does record that Ibrahim as caliph did confirm the appointment of Abdallah ibn Umar as governor of Iraq (v. 27, p. 13).