Andropov's health declined rapidly during the tense summer and fall of 1983, and he became the first Soviet leader to miss the anniversary celebrations of the 1917 revolution that November. He died in February 1984 of kidney failure after disappearing from public view for several months. His most significant legacy to the Soviet Union was his discovery and promotion of Mikhail Gorbachev. Beginning in 1978, Gorbachev advanced in two years through the Kremlin hierarchy to full membership in the Politburo. His responsibilities for the appointment of personnel allowed him to make the contacts and distribute the favors necessary for a future bid to become general secretary. At this point, Western experts believed that Andropov was grooming Gorbachev as his successor. However, although Gorbachev acted as a deputy to the general secretary throughout Andropov's illness, Gorbachev's time had not yet arrived when his patron died early in 1984.