AbstractIn 1064, Donnchad mac Briain, son of Brian Bóroma and deposed claimant to the kingship of Ireland, went on pilgrimage to Rome, where he was buried in the important basilica and martyr shrine of S. Stefano Rotondo on the Caelian Hill. More than a century later, in the transformative period 1176–1203 which followed the English conquest of Ireland, the papal legati a latere sent with full legatine authority and jurisdiction in Ireland appear to have been drawn exclusively from the church of S. Stefano. This article first considers the circumstances and symbolism of Donnchad's pilgrimage and burial, alongside its long-term impact on Hiberno-Papal relations and on the papacy's conceptions of Irish sovereignty in the eleventh and twelfth centuries. It also explores the careers and missions of the cardinal priests and papal legates of S. Stefano to the peripheries of Latin Christendom in the long twelfth century, including at least one legate in Ireland, Gerard, who has hitherto awaited formal identification. Based on the legatine evidence, it suggests that in the decades of the English invasion, the papacy began using the burial site of the heir to arguably the last effective king of Ireland as part of a conscious and consistent rhetorical strategy, allowing it to dispose matters of sovereignty in Ireland.