This chapter argues that Henry VIII’s conquest of Boulogne was one of the most important events of his reign and shows the need to revise our assumptions about a number of key aspects of Tudor history in light of English actions in France in the 1540s. It shows that form of military colonisation which Henry VIII employed at Boulogne set the tone for the Tudor monarchy’s expansionist strategy in Ireland and that there were a number of connections between the two zones of conquest. It reveals that men who had served in France in the 1540s were deployed to other frontiers, leading to a diffusion of skills and practices across the kingdom. The chapter also demonstrates that the severe military methods the English employed against the Irish in the sixteenth century were not exceptional, and it emphasises the formative role that service in France and Scotland played in the wider upsurge in violence across the English monarch’s dominions during the sixteenth century. This chapter also challenges the view that England was detaching itself from continental European concerns following the break with Rome in the 1530s and shows that Henry VIII’s efforts in the 1540s were principally focused on expanding his territories in France.