When and why did the Czar give up his throne?

Well, I wouldn't say he actually gave up his throne. It had more to do with the fact that he was dragged off it during the October 1917 Bolshevik revolution and had his throat cut or somesuch. He was dead, anyway, and so were all his family. Unfortunately, all the people got out of their revolution was Stalin, who made the Czar and any of his excesses look like a vacation in Hawaii. People feel sorry for the Jews. The Russians have had it at least as bad, if you ask me.