Athletic Bilbao, founded in 1898, is a professional football club located in the city of Bilbao in the Basque Country, Spain. It is nicknamed "The Basque Lions."
Athletic Bilbao is the fourth most successful club in La Liga, ranking second in the Copa del Rey championship list, only behind Barcelona. It is also the most successful Basque football club in winning league and cup titles.
The club is one of the three that has never been relegated from the top division since its establishment in 1929, the other two being Real Madrid and Barcelona. These three clubs, along with Osasuna, are the only four professional clubs in Spain that are not sports companies, owned and operated by club members.
Athletic Bilbao Football Club has a tradition that only athletes of Basque descent are allowed to be players. Players representing Bilbao are not restricted by nationality, but they must have Basque ancestry.