In the aftermath of the Third Carlist War (1876), Arana attended the Jesuit School of Orduña along with his brother Luis (1876–1881). Orduña became a hotspot and meeting point for the pro-"fueros", primeval Basque nationalists concerned with the loss of the Basque native institutions. Arana claimed that he had a quasi-religious revelation at Easter 1882, one that he communicated to his brother Luis Arana. From then he devoted himself to the nationalist cause of Biscay, later extended to the Basque Country.