loot from abbeys and cathedrals, cities and trading centres was the earliest and most convenient kind of profit, but it had the disadvantage of not being sustainable. Once a church treasury, with its accumulation of gold and silver over many years, had been looted, its plate melted down or cut up into shares, it would take many years for any accumulation to build again. Slaves were much more renewable (a development which the TV series on the whole ignores), and in Ireland this seems to have become the main reason for attacking church festivals and gatherings. Slaves could be very profitable indeed (as will be demonstrated later), but they had drawbacks too. They had to be guarded and transported. Worse, buyers had to be found for them – buyers with cash.