9 (a.k.a. Nonet), a chamber music formation, which was a realisation of a dream for Piazzolla and for which he composed some of his most sophisticated music. He now put aside his first Quinteto and made several recordings with his new ensemble in Italy. Within a year the Conjunto 9 had run into financial problems and was dissolved and in 1972 he participated in his first concert at the Teatro Colón in Buenos Aires, sharing the bill with other Tango orchestras. After a period of great productivity as a composer, he suffered a heart attack in 1973. That same year he moved to Italy where he began a series of recordings which would span a period of five years. The music publisher , a partner in Curci-Pagani Music, had offered Piazzolla a 15-year contract in Rome to record anything he could write. His famous album Libertango was recorded in Milan in May 1974. Later that year he separated from Amelita Baltar and in September recorded the album Summit (Reunión Cumbre) with the saxophonist Gerry Mulligan and an Italian orchestra, including jazz musicians such as bassist /arranger Pino Presti and drummer Tullio De Piscopo, in Milan. The album includes the composition Aire de Buenos Aires by Mulligan. In 1975 he set up his Electronic Octet, an octet made up of bandoneon, electric piano and/or acoustic piano, organ, guitar, electric bass, drums, synthesizer and violin, which was later replaced by a flute or saxophone. Later that year Aníbal Troilo died and Piazzolla composed the in his memory, a work in four parts, which he recorded with the Conjunto Electronico. At this time Piazzolla started a collaboration with the singer José Ángel Trelles, with whom he made a number of recordings. In December 1976 he played at a concert at the Teatro Gran Rex in Buenos Aires, where he presented his work, “500 motivaciones”, written especially for the Conjunto Electronico, and in 1977 he played another memorable concert at the Olympia in Paris, with a new formation of the Conjunto Electronico. In 1978 he formed his second Quintet, with which he would tour the world for 11 years, and which would make him world-renowned. He also returned to writing chamber music and symphonic works. During the period of Argentine military dictatorship from 1976 to 1983, Piazzolla lived in Italy, but returned many times to Argentina, recorded there, and on at least one occasion