In October 1641, after a bad harvest and in a threatening political climate, Phelim O'Neill launched a rebellion, hoping to rectify various grievances of Irish Catholic landowners. However, once the rebellion was underway, the resentment of the native Irish in Ulster boiled over into indiscriminate attacks on the settler population in the Irish Rebellion of 1641. Irish Catholics attacked the plantations all around the country, but especially in Ulster. English writers at the time put the Protestant victims at over 100,000. William Petty, in his survey of the 1650s, estimated the death toll at around 30,000. More recent research, however, based on close examination of the depositions of the Protestant refugees collected in 1642, suggests a figure of 4,000 settlers were killed directly; and up to 12,000 may have died of causes also related to disease (always a cause of high fatalities during wartime) or privation after being expelled from their homes.