In a first for troubled neighbors, Irish president makes state visit to UK as guest of queen

The President of Ireland, Michael D Higgins arrives at London Heathrow Airport for the first state visit by a President of Ireland to the United Kingdom, Monday April 7, 2014. This state visit by Higgins has been decades in the making and provides a poignant milestone for peacemaking between Ireland and UK following many years of conflict and division. (AP Photo / Steve Parsons, PA) UNITED KINGDOM OUT - NO SALES - NO ARCHIVES (The Associated Press)

FILE - In this Saturday, March 17, 2012 file photo, from left Irish President Michael D. Higgins, his wife, Sabina Coyne watch passing performers at St. Patrick's Day parade in Dublin, Ireland. Ireland's head of state is making his country’s first state visit to Britain this week, a trip that has been decades in the making and provides another poignant milestone for peacemaking. President Michael D. Higgins is flying Monday, April 7, 2014 to England a day ahead of his formal reception by Queen Elizabeth II at Windsor Castle west of London. Higgins’ tour, which runs through Friday, comes three years after the queen’s first state visit to the Republic of Ireland, which a British monarch had not visited since 1911. (AP Photo/Shawn Pogatchnik, File) (The Associated Press)

Ireland's president is being feted by Queen Elizabeth II at Windsor Castle, on a state visit heavy with symbolism for two countries with a tangled and troubled history.

President Michael D. Higgins' visit is the first by an Irish head of state since Ireland threw off British rule a century ago, and a sign of how Northern Ireland's peace process has transformed relations between two one-time enemies.

Higgins says that while it was impossible to "wipe the slate clean" about the past, relations between the two countries were good.

Higgins will address Britain's Parliament during his three-day trip, which includes a banquet Tuesday evening at the castle, hosted by the queen. Among the guests will be Martin McGuinness, once a senior IRA commander, now Northern Ireland's deputy leader.