He is known chiefly as one of key people behind the anti-Republican conspiracy in the vasco-navarrese area in the spring of 1936; thanks to his position of a businessman and army supplier, he procured arms and munitions for the rebels.

In 1937 he was for 5 months the provincial Gipuzkoan leader of the Francoist state party, the FET y de las JONS, but was shortly ousted as a zealous Carlist, non-compliant with the official regime ideology.

[2] The first direct ancestor of Agustín which can be traced is his strictly paternal great-grandfather Silvestre Antonio Tellería Ugalde, married to Clara Ignacia Lascurain Argarate[3] and living in Antzuola in the early 19th century.

[9] Following early death of his wife in 1882,[10] one year later[11] Telleria Oyarzabal re-married with Maria Esteban Mendizábal Elgarresta[12] (died 1913),[13] a girl from the nearby village of Urretxu and descendant to a family which already had been related to the Tellerías.

Tellería Oyarzabal owned one of 4 manufactures operational in the municipality and developed it into the most successful one, with branches in other Gipuzkoan locations;[15] it produced belts, footwear, holsters, saddles and other leather goods, mostly for the army.

[34] In the mid-1900s he engaged in the Carlist youth organisation and over time grew to president of the Tolosa branch of Juventud Carlista; it is not clear why he was not active in his native Vergara arm of the structures.

In 1908 he was already mingling with party executives in Gipuzkoa, e.g. he entered the committee headed by the provincial jefé Tirso de Olazabal and entrusted with organizing a grand regional Traditionalist rally in Zumarraga.

It seems that Tellería's party activity ceased; if referred in the press in the mid- and late 1920s, it is only on social columns[41] or in sporting sections, noted as sponsor of rowing teams.

[47] Later during the year he represented the Gipuzkoan Mellistas during a common rally in Pamplona,[48] campaigned with the “Jaungoikoa eta Foruak” slogan[49] and took part in Traditionalist feasts.

[52] He entered also the broad, 50-member national executive body; as “jefe militar de Vascongadas, Navarra y Rioja” he was responsible for buildup of the Carlist paramilitary organization requeté in the key, vasco-navarrese area.

At one point in 1933 the unofficial co-ordinator of nationwide requeté structures, colonel José Varela, relieved Tellería of his duties in Navarre, where Ignacio Baleztena took over.

[59] Apart from the usual propaganda activities,[60] in 1933 he stood in the province as a Traditionalist candidate for the Cortes;[61] though his 27,614 votes made a decent showing, he failed to make it to the parliament.

However, the party executive was divided over the strategy to be adopted: Fal and his followers[68] were gearing up for a stand-alone, exclusive Carlist rising, while another group[69] preferred to join the military when they decide to move.

[74] As the Carlist plan envisioned that at one point volunteers disguised as Guardia Civil would take control of key ministry offices in Madrid, Tellería took care of getting the uniforms ready.

Also in early March and as official supplier of leather products for the army,[75] he managed to get hundreds[76] of benemerita uniforms, produced on his order in Zaragoza, to be delivered to a Carlist depot in Madrid.

[88] The family Antzuola factory was now working for the Nationalist war machine[89] and in early 1937 he published[90] account of his days in the Republican zone as a booklet, El milagro de Agustín Tellería.

[91] In March 1937 the Republican court in Bilbao in course of formal proceedings declared Tellería guilty of rebellion and sentenced him to prison;[92] the same ruling was applied to his son, one month earlier killed in action.

In course of one of key meetings in Burgos[95] he questioned the legality of Consejo de la Tradición, a body formed by the Rodeznistas as part of their strategy to overpower Fal.

[97] He did, and returned excited;[98] he got convinced that the arrested Hedilla conspired against Franco, that with marginalisation of Falange “the moment is ours, entirely ours”, and that the Carlists should seize it and align with the military.

At this role he tried to ignore the Falangists, to pay due respect to the army and to advance Traditionalism as the political cause; when leading preparations to the first anniversary of Nationalist troops taking San Sebastián, he tried to format the gala as an exalted Carlist spectacle.

[104] On March 20, 1939, he lost control over his car on a slippery, poorly maintained road in Betoño, near Vitoria; he survived the crash,[105] but perished the following day in a hospital.