The historiography of Franco-Irish relations in the sixteenth and early seventeenth centuries has traditionally concentrated on commercial connections between the two countries and on the embryonic development of the Irish, and specifically the clerical, diaspora in France. Ireland's commercial ties with France in the late Middle Ages have been the subject of a substantial amount of specialised scholarly research that has broadly traced the principal trade routes, identified both Irish and French families involved in commercial networks and provided an insight into the practicalities of their business transactions. Arising from this exposition it is clear that Ireland had established trade links with the main ports of Normandy and those of the French Atlantic seaboard by the late fifteenth century. This trade survived the disruptions of legislative restrictions, war and piracy throughout the sixteenth century and increased in the early 1600s. While existing studies have examined Ireland's commerce with France in isolation, this study shows that when set within the wider context of sixteenth-century Franco-Irish relations, these connections, combined with Irish seafarers' familiarity with French ports, proved critical in facilitating the flight and safe harbouring of Ireland's political dissidents who sought asylum or assistance in France from 1540 onwards. Later they were to determine the destinations of the thousands of Irish migrants who fled to France during and in the immediate aftermath of the final contest in the Elizabethan conquest of Ireland, the Nine Years' War (1594–1603).