The president of Ireland is in the UK on the first visit of an Irish head of state.
Michael Higgins said that his country's fight for independence from the UK had cast a long shadow over their relationship.
The modern relationship between the UK and Ireland is more about economic prospects than historic grievances.
Higgins will be hosted at a banquet held by the British queen. Northern Ireland's deputy first minister, Martin McGuinness, a former member of the IRA, is also attending.
Al Jazeera's Paul Brennan reports from Windsor.
Source: Al Jazeera