On 23 October 1641, the Ulster Catholics staged a rebellion. The mobilised natives turned on the British colonists, massacring about 4000 and expelling about 8,000 more. Marianne Elliott believes that "1641 destroyed the Ulster Plantation as a mixed settlement". The initial leader of the rebellion, Felim O'Neill, had actually been a beneficiary of the Plantation land grants. Most of his supporters' families had been dispossessed and were likely motivated by the desire to recover their ancestral lands. Many colonists who survived rushed to the seaports and went back to Great Britain.