The rebellion quickly spread to the rest of Ireland. By the spring of 1642 only fortified Protestant enclaves, around Dublin, Cork and Derry, held out. King Charles I sent a large army to Ireland, which would probably have put down the rebellion, had the English Civil War not broken out. As it was, the Irish Catholic upper classes had breathing space to form the Irish Catholic Confederation, which acted as a de facto independent government of Ireland until 1649. Felim O'Neill was a member of the Confederate's parliament, named the General Assembly, but was sidelined in the leadership of Irish Catholics by wealthier landed magnates.