Despite being sentenced to a four-year prison term on 1 June 1933, he was temporarily released for surgery on his injured leg in March 1934. Following his release, Gomułka requested that the KPP send him to the Soviet Union for medical treatment and further political training. He arrived in the Soviet Union in June and went to the Crimea for several weeks, where he underwent therapeutic baths. Gomułka then spent more than a year in Moscow, where he attended the Lenin School under the name Stefan Kowalski. The ideology-oriented classes were arranged separately for a small group of Polish students (one of them was Roman Romkowski (Natan Grünspan -Kikiel), who would later persecute Gomułka in Stalinist Poland) and included a military training course conducted by Karol Świerczewski. In a written opinion issued by the school Gomułka was characterized in highly positive terms, but his extended stay in the Soviet Union caused him to become disillusioned with the realities of Stalinist communism and highly critical of the agrarian collectivization practice. In November 1935 he illegally returned to Poland.