That is a complex question to answer. In 1882 an Irish team
formed. Northern Ireland only came into existence in 1921 and at
that time a separate organisation to look after football in
Northern Ireland was formed. There were then two international
teams, both taking players from all around Ireland. It was not
until 1953, that a restriction was put on the team to only takes
its players from within Northern Ireland and for the first time the
name Northern Ireland was used for the team.