Complex sentence: In 1961, Letts joined the "Acción Popular" party and was head of the Chancay Provincial Committee of Acción Popular, he participated in the III National Congress of Acción Popular held in Iquitos.
Split into simpler sentences: In 1961, Letts joined the "Acción Popular" party and was head of the Chancay Provincial Committee of Acción Popular. He participated in the III National Congress of Acción Popular held in Iquitos.