In 1929, the club became one of the founding members of La Liga, Spain's first truly national league, and has since achieved the distinction of being one of only three clubs to have never been relegated, along with Real Madrid and Athletic Bilbao. Barcelona is the only European club to have played continental football every season since 1955. Barcelona holds a long-standing rivalry with Real Madrid, with matches between the two teams referred to as "El Clásico" (El Clàssic in Catalan).