The historic enmity between the Basque country’s two biggest cities, industrial Bilbao and aristocratic San Sebastian, found a sporting outlet when football arrived in the early 20th century.

Athletic Club, notably using the English spelling, was founded in 1898 by Bilbao-born engineering students who had studied in the United Kingdom. San Sebastian’s Real Sociedad de Futbol [Royal Society of Football] was soon established 100 kilometres along the coast in 1909, with the official seal of Spain’s King Alfonso XIII.

Exhibition and friendly games between the clubs immediately began, with the beginning of the Basque Regional League in 1913 bringing official status. A famous early derby in February 1914 was won 3-2 by Athletic, with the opener scored by legendary Los Leones striker Pichichi, whose name lives on in the trophy given to La Liga’s annual top goalscorer.

The rivalry continued with LaLiga’s introduction in 1928/29, as Athletic came from 0-2 down to win the first derby 4-2. Athletic’s Telmo Zarra – who was also the top all-time goalscorer in LaLiga until a certain Lionel Messi broke his record in 2014 – is the fixture’s leading goalscorer, including five goals in a 7-1 win at San Mames in 1950-51, still the biggest derby victory by either team. La Real’ all-time top scorer Jesus María Satrustegui got to 13 in his 16 derbis in the 1960s and 70s.

The early 1980s was a golden age for Basque football, with La Real winning their two LaLiga titles to date in 1980/81 and 81/82, and Athletic Club following up with a double in the next two years. A 1983-84 derby came on the season’s final day at San Mames, when Athletic's centre-half Iñigo Liceranzu scored twice in a 2-1 win which clinched the most recent of his club’s eight LaLiga trophies.

There have been 146 LaLiga Basque derbies to date, with Athletic winning 59 times, La Real 50, and 37 draws. Many players have featured for both clubs over the years, including former midfielder and current Athletic Club coach Gaizka Garitano. Only two players have scored for each side in the fixture, striker Rafa Iriondo in the 1950s and 60s and forward Pedro Uralde in the 1980s. Most recently, Athletic taking Spain international centre-back Iñigo Martinez from La Real in January 2018 always ensures a hot reception in San Sebastian.

However, while emotions can run high on derby day, both players and supporters at both clubs also realise how they have in common, including recently redesigned modern stadiums at San Mames and the Reale Arena. Home and away fans mix both outside and inside the grounds on derby day, with the red and white of Athletic mingling with Real Sociedad’s blue and white [txuri-urdin] throughout the city. Both on and off the pitch, the Basque derby shows much of what is positive about LaLiga.