Judo became popular in Russia after 1972 when the USSR Judo Federation was created, with Russian athletes winning medals in the Olympics. It was previously unknown until the early 1900s when some self-defense techniques from books were studied by the St. Petersburg police, and by 1990 the USSR Federation had become the Russian Judo Federation. Famous Russian judoka include Alexander Mikhailin, Vladimir Putin, Tamerlan Tmenov, Ivan Nifontov and Kirill Denisov.