With the Irish – even with the kings – [Patrick] succeeded beyond measure. Within his lifetime or soon after his death, the Irish slave trade came to a halt, and other forms of violence such as murder and intertribal warfare, decreased. In reforming Irish sexual mores, he was rather less successful, though he established indigenous monasteries and convents, whose inmates by their way of life reminded the Irish that the virtues of lifelong faithfulness, courage, and generosity were actually attainable by ordinary human beings and that the sword was not the only instrument for structuring a society.
Patrick’s relations with his British brothers were less than happy. Rising petty kings along the western coasts of Britain, rushing to fill the power vacuum left by the departure of the Roman legions, began to carve out new territories for themselves and to take up piracy, an activity the Christian Britons had long ago abandoned.Cahill, How the Irish Saved Civilization, p. 110
One important piece usually missing from contemporary discussions about slavery – ancient Christians abolished slavery in the Roman empire and even in territories beyond. Thus the modern abolition movement was the second time Western Christianity had ended slavery in its domains.