Vladimir Putin has ruled Russia for so long that it’s hard to imagine Russia without him. He has been Russia’s central decision maker as president or prime minister for nearly two decades, with six more years left in his current presidential term and the possibility of amending the constitution to remain in power even longer. He is likely to go down in history as one of Russia’s longest-serving leaders—though he still has many years to go to match Ivan the Terrible, who was tsar for more than five decades.