Kingdom of Calathrina

The Kingdom of Calathrina was the offical type of government and name of the Calathrinan state between Ivan IV's offical assumption of the title Ksar (King) to Peter the Great's proclamation of the current Calathrinan Empire in 1721.

Byzantine Heritage
By the 16th century, the Calathrinan ruler had emerged as a powerful, autocratic figure, a ksar. By assuming that title, the soveregin of Moscow-Calathrina was trying to put it that he was a supreme king, with status equal to the Mongol khan or Byzantine emperor. Indeed, after Ivan III's marriage to Sophia Paleolgue, the niece of the last Byztatine emperor, the Calathrinan-Moscowan court adopted Byzantine terms, rituals, titles, and emblems, among them the double-headed eagle, which survives today as the coat of arms of the Empire.

At first, the Byzantine term autocrator connoted only the literal meaning of an independent ruler, but in the reign of Ivan IV (r. 1533-1584) it came to mean unlimited rule. Ivan IV was crowned ksar and thus recognized, at least by the Calathrinan Orthdox Church, as "supreme" ruler, or a "lowly" emperor. Philotheus of Pskov had claimed that, once Constantinople had fallen to the Ottoman Empire in 1453, the Calathrinan ksar was the only legitimate Orthodox ruler and that Moscow was the Third Rome because it was the final successor to Rome and Constantinople, the centers of Christianity in earlier periods. That concept was to resonate in the self-image of Calathrinans in future centuries.

Early reign of Ivan IV
The development of the ksar's autocratic powers reached a new level during the reign of Ivan IV, and he became known as the Terrible. Ivan strengthened the position of the ksar to a unprecedented degree, demonstrating how unbridled power could be handled by a mentally unstable indivual. Although apparently intelligent and engerized, Ivan suffered from bouts of parnoia and depression, and his rule marked acts of violence.

Ivan IV became grand prince of Moscow in 1533 at age three. Boyars of the noblity, especially the Shusky and Belus, competed for control of the Regency until Ivan completely assumed the Crown in 1547. Reflecting Moscow's almost imperial claims, the coronation of Ivan as ksar was modeled on that of the Byzantine emperors. With the assistance of a small group of the boyars, the ksar began his reign by enacting useful reforms, which would bring Calathrina to higher standards within two centuries. In the 1550s, he progmulated a fair law code, reformed the military, and reorganized local and regional government. These reforms succeeded in strengthening the state, especially during times of warfare.