Mortimer became disaffected with his king and joined the growing opposition to Edward II and the Despensers. After the younger Despenser was granted lands belonging to him, he and the Marchers began conducting devastating raids against Despenser property in Wales. He supported Humphrey de Bohun, 4th Earl of Hereford, in refusing to obey the king's summons to appear before him in 1321 as long as "the younger Despencer was in the King's train." Mortimer led a march against London, his men wearing the Mortimer uniform which was green with a yellow sleeve. He was prevented from entering the capital, although his forces put it under siege. These acts of insurrection compelled the Lords Ordainers led by Thomas, 2nd Earl of Lancaster, to order the king to banish the Despensers in August. When the king led a successful expedition in October against Margaret de Clare, Baroness Badlesmere, after she had refused Queen Isabella admittance to Leeds Castle, he used his victory and new popularity among the moderate lords and the people to summon the Despensers back to England. Mortimer, in company with other Marcher Lords, led a rebellion against Edward, which is known as the Despenser War.