On April 20, 1913 Basque rugby team Aviron Bayonnais (Baionako Arrauna in Basque) defeated Paris-based SCUF (Sporting club universitaire de France rugby) 31-8 to be crowned champions of France for the 1912-13 season. It was the first time that the team–and indeed any Basque team–had won the championship, established in 1892. And it is still considered one of the great final championship deciders in the history of French rugby. See this ESPN article for a fuller account of the famous final.
What really marked this victory, and the team as a whole, was its spectacular playing style, known as the “Bayonnais way,” which revolutionized the rugby of that era. This was in the main down to Harry Owen Roe, a Welsh rugby player who had relocated to Baiona to work as a shipping clerk and join the ranks of the team. He introduced new methods of speed, offense, and “total rugby” (in which all members of the team, whatever their position, were encouraged to run at the opposition). This was copied from the Welsh style of rugby at that time and incorporated into the Aviron Bayonnais game, and this kind of play would have a huge impact on French rugby as a whole in the years to come. Indeed, for some it even represents the origins of what has been termed the “French flair” style of rugby.
Founded in 1904, Aviron Bayonnais subsequently finished runners-up in the championship two years in succession (1922 and 1923), losing out on both occasions to Stade Toulousain (still, today, one of the great forces in European rugby). However, the team went on to more success and indeed enjoyed its golden years during the 1930s and 1940s, winning the championship on a further two occasions, beating arch rivals Biarritz Olympique in 1934 and then, nearly a decade later, SU Agen in 1943. It contested two more championship finals, against USA Perpignan in 1944 and, most recently, against SU Agen in 1982, but was unsuccessful on both occasions.
If you’re interested in the topic, check out Alban David, Histoire du rugby au Pays Basque: De 1900 à aujourd hui. Éditions Sud Ouest, 2014.
See Cameron Watson’s Modern Basque History: Eighteenth Century to the Present for a general overview of sport (both traditional and modern) in Basque culture, including some discussion about the importance of rugby in Iparralde. This work is also available free to download here.