Acracio Martínez Prieto was born in Santurtzi as the son of an anarchist father, his named was changed to Horacio by the Bilbaocivil registry of the Ollerías neighborhood. Horacio studied at a municipal school, where he was beaten by his teacher - to which his father responded with a knife. Despite being a good student, Horacio did not receive any scholarship and had to immediately find work. As a teenager, he discarded all the predominant ideologies and instead formed a libertarian group, "Los sin patria". Horacio was saved from being lynched by a group of Basque nationalists, due to the intervention of a rival gang from the Bilbao neighborhood of Bolueta. He took up the habit of carrying a pistol, which landed him in the Larrinaga prison in Bilbao at only 18 years of age, where he came into contact with a variety of different comrades. An attack in Altos Hornos de Vizcaya meant for Horacio the beginning of a long series of dangerous incidents, which forced him into exile in France, leaving his mother, already a widow, in Bilbao. Not long after Primo de Rivera's coup in 1923, Horacio participated in an attempted anarchist takeover of Vera de Bidasoa, but managed to escape again. In 1931, when the Second Spanish Republic was proclaimed, he joined the CNT. In 1932 he was invited by the PCE to visit Russia along with the director of Tierra Vasca, but he returned with unfavorable impressions - he was initially cautious in sharing his views but later published a pamphlet that was critical of the Soviet system. Following the CNT's participation in the Revolution of 1934, he took the post of Deputy Secretary of the CNT, and in 1935 at the Congress of Zaragoza, Prieto replaced Miguel Yoldi as the CNT's general secretary. The outbreak of the Spanish Civil War surprised Prieto in Bilbao, where he represented the CNT in the Basque Defence Council until he moved to Barcelona. Due to his proposal to involve the CNT in the governments of Azaña and Largo Caballero, he was accused of being a traitor and a liquidationist, which led him to resign from his post in November 1936, although he continued representing the Northern Region in the CNT's National Committee and as a member of the Political Advisory Commission, from where he defended the participation of the CNT in the government of the Second Spanish Republic. Affiliated with the FAI, he was general director of commerce under the ministry of Juan López Sánchez and Undersecretary of Health under Segundo Blanco. From the magazine Timón , directed by Diego Abad de Santillán, he defended his view that the FAI be transformed into a political party. At the same time he was part of an alliance committee with the UGT and called for the opening of negotiations with the Nationalist faction. At the end of the war he went into exile, where he was a leading member of the Spanish Libertarian Movement, defending anarchist participation in the Spanish Republican government in exile. He was Minister of Development in the two governments of José Giral and was one of the signatories of the manifesto of January 23, 1948 calling for the transformation of the MLE into a political party. Horacio Martínez Prieto died in his Parisian exile, leaving six volumes of memoirs and several pamphlets on anarcho-syndicalism, the USSR and the future of the CNT unpublished.
