The club was founded in 1887 and began playing league football in 1890 as founder members of the Scottish Football League.
[2] Celtic played their inaugural league fixture as part of the 1890–91 Scottish Football League on 23 August 1890 against Heart of Midlothian.
Since that game they have faced 45 different sides in league football with their most regular opponent having been their Old Firm rivals Rangers, whom they have played on 330 occasions since their first league meeting on 21 March 1891.
They have drawn more matches with Rangers than with any other club with 90 of their meetings finishing without a winner.
[3] Rangers are also the side that has defeated Celtic in more league games than any other club, having won 127 of their encounters.