Between the 1930s and 1970s, the Scottish football club Rangers had an unwritten rule whereby the club would not knowingly sign any player who was a Roman Catholic.[1][2] This was because Rangers were viewed as a Protestant, Unionist club, in contrast to their Old Firm rivals, Celtic who were viewed as an Irish Catholic club, although Celtic never adopted a similar signing policy. Rangers' policy was ended in 1989 when they signed ex-Celtic striker Mo Johnston, under manager Graeme Souness.