 At the time the population of his estates was estimated to have been about 12,000, and in consequence he would have been a power to be reckoned with within the Highlands.According to A and A Macdonald, it seems that the baronet had not been very enthusiastic for the royal cause.In the autumn of 1644, when Alasdair MacColla arrived on the west coast, with Irish auxiliaries supplied by the Marquess of Antrim, he offered command to Sleat, yet Sleat declined the offer.