In early August 1540 Lord Leonard Grey's successor, Sir Anthony St Leger, arrived in Ireland to begin an eight-year term of office as lord deputy. This led to a change in the tenor of domestic and Anglo-Irish political relations which in turn profoundly shaped the character of Franco-Irish relations. During the early and mid-1540s the altered dynamic of Ireland's contacts with France resulted in a temporary aberration in their relations in two key respects. First, thanks to the success of St Leger's conciliatory policy in handling the most powerful Gaelic and Anglo-Irish lords, the early and mid-1540s witnessed none of the opportunistic contrivance with the French that had characterised previous decades. This was manifest in the refusal by both Anglo-Irish and Gaelic lords to respond to rumours of Gerald Fitzgerald leading a French invasion of Ireland that were little more than war propaganda deliberately circulated by Henry's French opponents in 1543–6 as one means of securing French victory over England. Second, in an unprecedented show of support for their newly-declared king, these lords mustered Gaelic soldiers for service in Henry's army in the Anglo-Scottish (1542–9) and Anglo-French (1543–6) wars at a time when his position and the security of the British Isles was particularly vulnerable.

St Leger's occupancy of the lord deputyship was critical in maintaining the fragile peace and stability that resulted in both Irish abstinence from involvement in intrigue with France and consequent minimal demands for financial, military and naval resources from the English privy council to fortify Ireland's defences.