How old was Mikhail Gorbachev when he ecame a member of the Politburo ?
On 23 April 1985 Gorbachev brought his two proteges Yegor Ligachev , and Nikolai Ryzhkov into the Politburo as full members , and sensibly took the opportunity to keep the ' power ' ministries happy by promoting KGB Head Viktor Chebrikov from candidate to full member of the Politburo , and appointing Minister of Defence Marshal Sergei Sokolov a Politburo candidate member .