On 13 August 1966, St. Mirren midfielder Archie Gemmill became the first substitute in Scotland.
The use of substitutes in football dates back to the 1860s, but as the rules became codified, they became disfavored and disallowed. By the 1950s, however, people began reintroducing them, with FIFA allowing them in qualification matches for the 1954 World Cup.
England and Scotland slowly began to reconsider the rule, with England adopting the use of a single substitute per team starting with the 1965-66 season, but even then only to replace an injured player. One year later, Scotland applied an identical rule.
Gemmill, then just 19 years old and two years into his career with St. Mirren, was the first player in Scotland to come on as a substitute, replacing an injured Jim Clunie after 23 minutes in a Scottish League Cup match against Clyde. Unfortunately for Gemmill and St. Mirren, it was a milestone made in a losing effort, as they fell to Clyde 1-0.
Gemmill went on to enjoy a lengthy career in Scotland and England (and a brief spell in the United States) that lasted until his retirement in 1984. He also earned 43 caps for Scotland, for whom he scored one of the World Cup's most memorable goals in a 1978 match against the Netherlands.