Given this paragraph about composer Arvo Pärt, tell me where and when he studied composition and with which teacher.

Context: Pärt's musical education began at the age of seven when he began attending music school in Rakvere. By his early teenage years, Pärt was writing his own compositions. His first serious study came in 1954 at the Tallinn Music Middle School, but less than a year later he temporarily abandoned it to fulfill military service, playing oboe and percussion in the army band. After his military service he attended the Tallinn Conservatory, where he studied composition with Heino Eller and it was said of him, "he just seemed to shake his sleeves and the notes would fall out". During the 1950s, he also completed his first vocal composition, the cantata Meie aed for children's choir and orchestra. He graduated in 1963.

Answer: Arvo Pärt studied composition at the Tallinn Conservatory during the 1950s. His composition teacher was Heino Eller.