As a result, although Frederick accepted the crown and entered Prague in October 1619, his support gradually eroded over the next few months. In July 1620, the Protestant Union proclaimed its neutrality, while John George of Saxony agreed to back Ferdinand in return for Lusatia, and a promise to safeguard the rights of Lutherans in Bohemia. A combined Imperial-Catholic League army funded by Maximilian and led by Count Tilly pacified Upper and Lower Austria before invading Bohemia, where they defeated Christian of Anhalt at the White Mountain in November 1620. Although the battle was far from decisive, the rebels were demoralised by lack of pay, shortages of supplies, and disease, while the countryside had been devastated by Imperial troops. Frederick fled Bohemia and the revolt collapsed.