NEW : Sinn Fein leader Gerry Adams says it is `` a good day for Ireland '' and the world '' Queen Elizabeth II lost a relative , Lord Mountbatten , to an IRA bomb in 1979 . The meeting would have been unthinkable a decade ago .
NEW : Sinn Fein leader Gerry Adams says it is `` a good day for Ireland '' Martin McGuinness speaks of the need to acknowledge the pain of all victims . Queen Elizabeth II lost a relative , Lord Mountbatten , to an IRA bomb in 1979 . The meeting would have been unthinkable a decade ago .