Belfast Northern Ireland United Kingdom - David Trimble (c) Leader of the Protestant Ulster Unionist Party (uup) and Party Arrive at the Historic First Session of the Newly-elected Northern Ireland Assembly at Stormont Castle in Belfast 01 July 1998 the 108 Members Elected 25 June Chose Trimble As First Minister and Seamus Mallon Deputy Leader of the Catholic Social Democratic and Labour Party (sdlp) As Deputy