Born in San Sebastián ( Basque Country ) , he did not learn the Basque language until the age of 17 , but came to be considered one of the most influential figures in Basque nationalism and culture in the second half of the 20th century .
Even though he did not learn the Basque language until he was 17 , he came to be seen as one of the most influential figures in Basque nationalism and culture in the second half of the 20th century .