glen2Glen - Remember that Cromwell was involved as a parliamentary commander in the middle of a civil war that was by no stretch of the imagination restricted purely to England. The Irish had been in rebellion in support of King Charles for almost eight years prior to Cromwell's arrival in Ireland. That rebellion was supported by Spain with the tacit agreement of the Stuart monarchy - treason in the eyes of Parliament. If decisive action was not taken in Ireland there existed a creditable threat of invasion of England backed by Spain. In this context it should also be remembered that the Spanish Armada (1588) was still, in historical terms, a fairly recent event.

The perception seems to be that Cromwell treated the Irish rebels in a harsher manner than the forces opposing Parliament on the mainland (i.e. England and Scotland). If that perception of the treatment of the Irish is true, it is only marginally so. The loss of life in his campaign in Scotland was held below that of his campaign in Ireland because of two factors. His campaign in Scotland was decided by set piece battles after which his Scottish captives were sent to work as slaves on the plantations of newly captured Jamaica. They still died, but not during the campaign.

The predominant feature of his campaign in Ireland was the investment and storming of fortified and garrisoned towns and cities. Remember that the rebels/Royalists in Ireland had had years to entrench themselves and were therefore tougher opposition. The unfortunate but established norm for such operations (and there are many such examples in history, from Troy until the seige of San Sebastion during the Napoleonic Wars) was that once beseiged a town was invited to surrender, if it did, all well and good, the population and garrison were afforded safe conduct. If, on the other hand, they did not surrender and forced the beseigers to take the town by force, then the town and it's inhabitants were generally given no quarter. The reasoning behind this being that the commander of the forces attacking knew his casualties would be far higher than in a fixed battle and the prospect of plunder was the only incentive he could give his troops to storm the city beseiged.