Maslama ibn Abd al-Malik
Umar is often deemed a pacifist by the sources and Cobb attributes the caliph's war-weariness to concerns over the diminishing funds of the Caliphate's treasury. Wellhausen asserts that Umar was "disinclined to wars of conquest, well-knowing that they were waged, not for God, but for the sake of spoil". Indeed, shortly after his accession in late 717, he ordered the withdrawal of the Muslim army led by his cousin Maslama ibn Abd al-Malik from their abortive siege against Constantinople to the region of Malatya, closer to the Syrian frontier. Despite the withdrawal, Umar kept up the annual summer raids against the Byzantine frontier, out of the obligation to "jihad". Umar remained in northern Syria, often residing at his estate in Khunasira, where he built a fortified headquarters.