But changes in political conditions compelled him periodically to rewrite the record. In February 1923, Yaroslavsky wrote a long article on Trotsky's early career, covering 1900-1902, in which he declared that   The campaign to denigrate Trotsky began that same year. Writing in the 1930s, Trotsky claimed that "Yaroslavsky rose to his present position entirely by his slandering of me. As the official corrupter of the history of the party, he represents the past as an unbroken struggle of Trotsky against Lenin." Yaroslavsky suddenly came under attack in 1931, when Stalin published an essay on the alleged mistakes made by historians, and claimed that "even Comrade Yaroslavsky is not, unfortunately, an exception; his books on the history of the CPSU (B), despite all their merits, contain a number of errors in matters of principle and history." Stalin did not say what the 'errors' were, but others picked up the attack, accusing Yaroslavsky of being a Trotskyist, a Menshevik etc. He wrote several plaintive letters to Stalin, but got no reply, so wrote a letter confessing to being in the wrong. He then wrote a new biography of Stalin that magnified his role in early Bolshevik history. After the rise of Nazi Germany, and of Japanese expansionism, there was a sudden change in the demands made on historians. In the 1920s, the Soviet Union's most eminent historian had been Mikhail Pokrovsky, who had depicted Russia under the Tsars as an aggressor that persecuted smaller nations such as the Jews and Poles, and which shared the blame for the outbreak of war against France in 1812, Japan in 1905, and Germany in 1914. With the renewed threat of war, Stalin proposed to appeal to Russian nationalism and tales of military glory. In 1939, Yaroslavsky denounced Pokrovsky as a Trotskyite, saying that:  Yaroslavsky was Chairman of the Society of Old Bolsheviks in 1931, until Stalin ordered the society's dissolution in 1935. He was also the head of the Society of Former Political Prisoners and Penal Exiles, a fraternal benefit society which aided Old Bolsheviks and other political prisoners of the Tsarist era. He was a member of the Party Control Commission in 1934-39. From 1939, he was a member of the Central Committee. With the outbreak of the German-Soviet War, in the summer of 1941, the Soviet state reduced its anti-religious activities in an effort to make use of the Russian Orthodox Church as an institution to rally the population to defend the nation.