Much of Cromwell's power was due to the Rump Parliament, a Parliament purged of opposition to grandees in the New Model Army. Whereas Charles I had been in part restrained by a Parliament that would not always do as he wished (the cause of the civil war), Cromwell was able to wield much more power as only loyalists were allowed to become MPs, turning the chamber into a rubber-stamping organisation. This was ironic given his complaints about Charles I acting without heeding the "wishes" of the people. Even so, he found it almost impossible to get his Parliaments to follow all his wishes. His executive decisions were often thwarted, most famously in the ending of the rule of the regional major generals appointed by himself.