The destruction of war was evident everywhere. Dr William Petty, the Army’s Physician-General, estimated that 504,000 native Irish and 112,000 colonists and English troops had perished between 1641 and 1652. Petty reckoned that another 100,000 Irish men, women and children had been forcibly transported to the colonies in the West Indies and in North America.William Petty was Oliver Cromwell's Chief Physician. Historians estimate an Irish population of 1.4 million before Oliver Cromwell decimated the Irish population. So almost 1/2 the population was killed or sent into slavery. This was genocide.