In what year was the team founded that won the 1956-1957 Irish League championship?
1956–57 Irish League The Irish League in season 1956–57 comprised 12 teams, and Glenavon won the championship.
Football Association of Ireland The Football Association of Ireland (FAI; Irish: "Cumann Peile na hÉireann" ) is the governing body for association football in the Republic of Ireland. It should not be confused with the Irish Football Association which is the governing body in Northern Ireland.