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.
Clarence F.C. Clarence Football Club is a former Irish football club based in the Belfast. It was founded in 1882 and was a founding member of the Irish Football League in 1890. The club resigned at the start of the 1891-92 season without playing any matches, having been unable to raise a team for its opening fixture. By the end of the 1891-92 season the club had folded.