The intimate friendship between Pavel Borisovich Axelrod and Karl Kautsky, stretching over almost half a century, had an important bearing on the Russian Social Democratic movement and international socialism. Kautsky, who, after Engels’ death in 1895, became the most authoritative exponent of Marxism and the major theorist of the Second International, followed developments in Russia with interest and leaned heavily on Axelrod in forming his opinions about events in that country and its Social Democratic Party. The German socialist's curiosity was aroused not only because he recognized, as early as the 1890s, the potential importance of the Marxist movement in Russia but also because Russian Marxists were especially eager to obtain his advice. “Whenever a controversial question arose,” wrote the Menshevik Rafael Abramovich, “whenever a problem emerged, the first thought [among Russian Social Democrats] was always: What would Kautsky say about this? How would Kautsky resolve this question?“