An Irish diplomat laid a wreath at the Cenotaph war memorial in London for the first time in almost 70 years on Sunday, in a further step in warming relations between Britain and Ireland.
The Irish ambassador to Britain Dan Mulhall laid a laurel wreath in the remembrance ceremony after accepting an invitation.
It is the latest in a series of symbolic gestures of reconciliation between Britain and Ireland that have marked a high point in their relations after a troubled history.
A historic visit by Queen Elizabeth II to Ireland in 2011 was the first made to the republic of Ireland by a British monarch.
It was followed by a state visit to Britain by Irish President Michael D. Higgins, the first by an Irish president.
Irish ambassadors have attended the remembrance ceremony at the Cenotaph before, but have not been invited to lay a wreath for Irish soldiers.
Over 200,000 Irish soldiers fought in the First World War, and 49,000 were killed.
Prime Minister Enda Kenny welcomed the wreath-laying.