Ivan

Ivan is a Russian form of John. The name is most famous for belonging to Ivan the Great, and to Ivan the Terrible, as well as Ivan Pavlov (as in "the Pavlov response.") Ivan has become a reasonably common name in the United States, having been consistently in the top 200 names for baby boys since 1990, although it should be noted that the name in Russia is pronounced a little like Yvonne, while in the U.S. it is with a long I sound (EYE-van.)