Ivan IV, known as Ivan the Terrible, is proclaimed Grand Prince of Moscow on December 4, 1533, at the age of three after the death of his father, Grand Prince Vasily III. He ruled under the regency of his mother, Yelena Glinskaya, until her death in 1538.
His mother's death was followed by a period of intense power struggles among nobles. Ivan was crowned "Tsar and Grand Prince of all Russia" on January 16, 1547, at the age of 16, marking the beginning of a new era for Russia, with a more centralized and powerful ruler at its head.