 Complete the following phrase:  Following the death of al-Walid I, Sulayman took up the project to capture Constantinople with increased vigor. In late 716, upon returning from the Hajj pilgrimage to Mecca, Sulayman encamped and mobilized his army in Dabiq in northern Syria. From there, he oversaw the massive war effort against the Byzantines. Being too ill to lead the campaign in person, he dispatched his half-brother Maslama ibn Abd al-Malik to 