You're right, he did. From wiki: "Because of constitutionally mandated term limits, Putin was ineligible to run for a third consecutive presidential term in 2008. The 2008 presidential election was won by Dmitry Medvedev, who appointed Putin Prime Minister. In September 2011, after presidential terms were extended from four to six years, Putin announced he would seek a third term as president. He won the March 2012 presidential election..."