Japanese Emperor Akihito and Empress Michiko left Ireland early Tuesday, heading to Norway on the next leg of a two- country European trip. The two had arrived in Ireland on Saturday and during their trip met with a number of dignitaries including Prime Minister (Taoiseach) Bertie Ahern and President Mary McAleese, with whom they had lunch on Sunday. Japan and Ireland have throughout their histories enjoyed friendly bilateral ties with few regions of conflict. During the Second World War, Ireland remained neutral in spite of its being a member of the British Commonwealth of Nations. In 1964, the Japanese legation in Ireland was upgraded to an embassy, while Ireland established and embassy in Tokyo in 1973, DPA said. The trip is their first overseas visit for Emperor Akihito and Empress Michiko since a 2002 tour of Central and Eastern Europe. The imperial couple are to spend four days in Norway, where they will meet with Crown Prince Haako Magnus, who will formally welcome the Japanese couple on behalf of King Harald V, who recently underwent heart surgery.