Timur himself, at the head of his central army, arrived before Smyrna on 2 December 1402 (6 Jumada al-Awwal 805). He then ordered the left army under his grandson Muhammad Sultan Mirza and the right army under his son Miran Shah to join him. The central army began to bombard the fortifications across the isthmus with stone-throwers immediately, and set to work on undermining the walls.[3] At some point, the ditch was infilled.[9] Large covered platforms with huge wooden wheels were rolled up to the outer wall.