State visit of the President of Ireland to the United Kingdom with full cavalry escort to Windsor Castle, where the President, accompanied by the Duke of Edinburgh, inspected a Guard of Honour provided by the 1st Battalion Irish Guards. President Higgins presented a ceremonial red coat to its regimental mascot, an Irish Wolfhound called Domhnall of Shantamon. The President viewed Irish-related items from the Royal Collection at Windsor Castle. Afterwards they departed for London and visited Westminster Abbey for a tour, where the President laid a wreath at the Grave of the Unknown Warrior and paid his respects with a bow to the tomb of Louis, the Earl of Mountbatten. After
The Unknown Warrior as tens of thousands of mourners filed silently past. The ceremony appears to have served as a form of catharsis for collective mourning on a scale not previously known. The grave was then capped with a black Belgian marble stone (the only tombstone in the Abbey on which it is forbidden to walk) featuring this inscription, composed by Herbert Edward Ryle, Dean of Westminster, engraved with brass from melted down wartime ammunition. Around the main inscription are four New Testament quotations: A year later, on 17 October 1921, the unknown warrior was given the United States' highest award for valour,