Another body established under the Good Friday Agreement, the British–Irish Council, is made up of all of the states and territories of the British Isles. The British–Irish Parliamentary Assembly (Irish: Tionól Pharlaiminteach na Breataine agus na hÉireann) predates the British–Irish Council and was established in 1990. Originally it comprised 25 members of the Oireachtas, the Irish parliament, and 25 members of the parliament of the United Kingdom, with the purpose of building mutual understanding between members of both legislatures. Since then the role and scope of the body has been expanded to include representatives from the Scottish Parliament, the National Assembly for Wales, the Northern Ireland Assembly, the States of Jersey, the States of Guernsey and the High Court of Tynwald (Isle of Man).

What was one of organizations that was founded because of the Good Friday Agreement?