In
1898 several
alumni of Castres' municipal college met in a city centre bar and decided to create a team allowing them to play their favourite sport,
rugby union. For the first few years this team was part of a
multisport club until
1906. Unhappy with the dominating position
cycling had within the club, the members of the rugby section decided to leave and create a club of their own, solely dedicated to their sport. It was decided that this club would be named
Castres Olympique and its colours would be changed from yellow and black to its current blue, white and grey. The new club reached the top flight after only 15 years of existence and has remained there ever since, bar for a couple of years during the 80s when the club was in the then Section B of the 1st division. The club has never left the 1st division since 1921. For a while Castres Olympique would experience mixed fortunes until
1948 when they reached and won their first
Coupe de France. The prestigious championship would follow a year later, and again in
1950. From the 1960s the club would experience a stream of mediocre seasons and steady decline until
Pierre Fabre, the founder of a local
pharmaceutical company, decided to take over the club and restore it to its former relative glory in
1988. In 1993, Castres played the final of the
1993 French Rugby Union Championship against
Grenoble, a team who was nicknamed "the mammoths", because of its incredibly physical forward pack, coached by the former French national team manager
Jacques Fouroux. Castres won its third national title 14–11, in a controversial match. Indeed, a try of
Olivier Brouzet is denied to Grenoble and the decisive try by
Gary Whetton was awarded by the referee, Daniel Salles, when in fact the defender Franck Hueber from Grenoble touched down the ball first in his try zone. This error gave the title to Castres. Salles admitted the error 13 years later.
Jacques Fouroux, being already suspicious before the match of the referee, saw in this outcome a conspiracy of his enemies from inside the rugby union French Federation. The club reached the final again in
1995 losing 31–16 to
Stade Toulousain. Castres won the 2012–13
French Rugby Union Championship beating
Toulon 19–14 in the final. Castres home stadium, previously known as Stade Pierre-Antoine, was renamed in his memory during ceremonies in conjunction with Castres match with
Montpellier on 9 September 2017. Castres won the 2017–18
French Rugby Union Championship beating
Montpellier 29–13 in the final. After finishing first in the 2021-2022 Top 14, Castres played a semi-final against the
Stade Toulousain of
Antoine Dupont and
Romain Ntamack, beating them 24–18. The final is a rematch of 2018, but this time, Montpellier win 29–10. ==Honours==