Famine and plague were the biggest killers, resulting in large part from the scorched earth tactics used by Parliamentary forces.
Those Catholic landowners deemed innocent of rebellion against the Parliament but who had not shown "constant good affection" still had their land confiscated and were forced to relocate to Connacht, where the soil was poorer.
[3] The Scottish Presbyterian community was also disadvantaged by the Interregnum regime, as most of them had taken the Solemn League and Covenant and had fought with the Scots against the Parliament in the Third English Civil War (1649–50).
Henry Cromwell, who replaced Fleetwood in 1655, was seen as a more conservative influence, conciliating the "Old Protestant" landed class and allowing the harshest legislation against Catholics (such as a ban on their living in towns) to lapse.
Towards the end of the Interregnum, Parliamentarian generals Charles Coote and Richard Boyle (who were also pre-war English settlers) seized the strongholds in Ireland in preparation for the restoration of the monarchy.