Edward began to plan his revenge. With the help of Pembroke, he formed a small coalition of his half-brothers, a few of the earls and some of the senior clergy, and prepared for war. Edward started with Bartholomew de Badlesmere, 1st Baron Badlesmere, and Isabella was sent to Bartholomew's stronghold, Leeds Castle, to deliberately create a "casus belli". Bartholomew's wife, Margaret, took the bait and her men killed several of Isabella's retinue, giving Edward an excuse to intervene. Lancaster refused to help Bartholomew, his personal enemy, and Edward quickly regained control of south-east England. Alarmed, Lancaster now mobilised his own army in the north of England, and Edward mustered his own forces in the south-west. The Despensers returned from exile and were pardoned by the royal council.