[7] The youngest son and Daniel's father, Manuel Irujo Apastegui (1803–1871), entered the Pamplona seminar but abandoned it[8] and completed law in Zaragoza, where he initially practiced.

[42] Education in Orduña college, managed by the Jesuits, is likely to have reinforced this stand; also during academic years in Valladolid Irujo remained in the company of Carlism-minded friends.

He seemed heavily influenced by his brother-in-law Estanislao Aranzadi, co-founder of Asociación Euskara de Navarra and its daily, Lau-buru;[44] politically the grouping tended to fuerismo,[45] with return to foral regime placed as the central if not exclusive objective.

[46] Apart from personal links and subscription to fuerista periodicals Irujo did not engage politically[47] before in 1887 he was offered a job in the Jesuit Deusto college.

[49] It advanced a thesis that until 1839 Navarre and the Vascongadas enjoyed the status of sovereign entities, united with the rest of peninsula mostly by means of personal union.

[53] When in Bilbao Irujo resumed his friendship with the Arana brothers and in 1894 he subscribed to their review Bizkaitarra,[54] though he did not join the early Basque nationalist organisation, Euskeldun Batzokija.

[58] Irujo's defense line was that Arana violated no law;[59] he went on to claim that his client campaigned against 1841 regulations, which he was perfectly entitled to do, apart from representing legitimate aspirations of "pueblo euskaldun", embodied in the God and Old Rights slogan.

In 1897 Irujo was asked to review El Partido Carlista y los Fueros Vasko-Nabarros, a pamphlet written by Arana and denouncing the Carlist vision as "plain regionalism".

[62] Formally Irujo was to ensure that the document provides no basis for legal action;[63] it is neither clear whether he contributed to the political content nor how he reconciled the task with his Carlist identity.

Prior to the 1898 elections to the Biscay diputación provincial Sabino Arana suggested that Irujo runs as his representative, but the latter declined the offer.

[67] In 1902 Sabino Arana was detained in relation to a telegram message he intended to send to president Roosevelt, congratulating him on recognition of Cuba, until 1898 the Spanish possession.

In general terms the defense mounted was very much similar to that of 1896, pointing to Basque rights and revocation of the 1840s regulations;[68] Irujo reiterated his claim that nationalism was not equal to separatism.

Around 1904 he returned to his native city; exact reasons remain unclear and perhaps are related to taking care of local family business.

[88] In 1908 the Aranista Centro Vasco of Bilbao used the services of Irujo's brother-in-law Aranzadi to offer the Estella city a shoot from the Guernica oak, a symbol of vasco-navarrese fueros.

[89] Irujo passed the proposal to ayuntamiento,[90] which accepted the offer[91] and in a pompous ceremony few months later planted the shoot at a patio of a local school.

[92] Navarrese press remained largely sympathetic, but a Liberal daily raised alarm, claiming that the local self-government fuels Basque separatism.

[93] As nationwide press followed suit the issue turned into a scandal, especially that the ceremony was marked by Basque and Navarrese flavor with almost total absence of official references to Spain;[94] moderate Irujo's address[95] was interrupted by angry "Viva España!"

[96] The council declared they had been unaware that the shoot originated from Centro Vasco and suggested having been maneuvered into a separatist affair, blaming Aranzadi and Irujo for the miscommunication.

Another Carlist in the council, Nicanor Larráinzar Senosiáin, led an all-out charge on Irujo, also publicly,[106] claiming that his support for the Aranistas was incompatible with Carlism.

[109] In a public letter to Olazábal Irujo considered himself disauthorised; speculating that apparently he had been erroneous as to fuerista objectives of the Carlists, he declared leaving Carlism.

[119] Deprived of anti-Spanish venom[120] and far from classic separatism, it envisioned Vasco-Navarrese area as sovereign entities united with other Spanish political bodies by a common monarch.

Another scholar considers Irujo a typical case of transitory identity from Carlism[125] to peripheral nationalism,[126] parallel to those of Vayreda (Catalonia), Brañas (Galicia) and Pereda (Cantabria).