Coat of arms
The Grand Duchy of Moscow (Russian: Великое княжество Московское) was a medieval Russian polity centred on Moscow between 1340 and 1547. The Grand Duchy of Moscow, as the state is known in Russian records, has been referred to by many Western sources as Muscovy, however, this term is also sometimes applied to the Tsardom of Russia. The Grand Duchy of Moscow was the successor to the Principality of Moscow and the predecessor of the Tsardom of Russia.

Origin
Ivan's successors continued gathering Russian lands to increase the population and wealth under their rule. In the process, their interests clashed with the expanding Grand Duchy of Lithuania, whose subjects were predominantly East Slavic and Orthodox. Grand Duke Algirdas of Lithuania allied himself by marriage with Tver and undertook three expeditions against Moscow (1368, 1370, 1372) but could not take it. The main bone of contention between Moscow and Vilnius was the large city of Smolensk.
In the 1350s, the country and the royal family were hit by the Black Death. Dmitry Ivanovich was aged nine, when his parents died and the title of Grand Duke slipped into the hands of his distant relative, Dmitry of Suzdal. Surrounded by pagan Lithuanians and Muslim nomads, the ruler of Moscow cultivated an alliance with the Russian Orthodox Church, which experienced a resurgence in influence, due to the monastic reform of St. Sergius of Radonezh.
Educated by Metropolitan Alexis, Dmitri posed as a champion of Orthodoxy and managed to unite the warring principalities of Russia in his struggle against the Horde. He challenged the Khan's authority and defeated his commander Mamai in the epic Battle of Kulikovo (1380). Although political advantages from the battle were nullified during Tokhtamysh's invasion of Russia several years later, Dmitri successfully overcame the stigma of collaborating with the Tatars which had been attached to Moscow for decades. In 1389, he passed the throne to his son Vasily I without bothering to obtain the Khan's sanction.

Vasily I and Vasily II
Outward expansion of the Grand Duchy in the 14th and 15th centuries was accompanied by internal consolidation. By the 15th century, the rulers of Moscow considered the entire Russian territory their collective property. Various semi-independent princes of Rurikid stock still claimed specific territories, but Ivan III (the Great; r. 1462–1505) forced the lesser princes to acknowledge the grand prince of Moscow and his descendants as unquestioned rulers with control over military, judicial, and foreign affairs.
Moscow gained full sovereignty over a significant part of the ethnically Russian lands by 1480, when the Tatars' Golden Horde overlordship ended officially after the Great standing on the Ugra river, and by the beginning of the 16th century virtually all those lands were united, including the Novgorod Republic (1478) and the Grand Duchy of Tver (1485). Through inheritance, Ivan was able to control the important Principality of Ryazan, and the princes of Rostov and Yaroslavl' voluntarily subordinated themselves to him. The northwestern city of Pskov remained independent in this period, but Ivan's son, Vasili III (r. 1505–33), later conquered it.
Having consolidated the core of Russia under his rule, Ivan III became the first Moscow ruler to adopt the titles of tsar and "Ruler of all Rus'". Ivan competed with his powerful northwestern rival Lithuania for control over some of the semi-independent former principalities of Kievan Rus' in the upper Dnieper and Donets river basins. Through the defections of some princes, border skirmishes, and a long, inconclusive war with Lithuania that ended only in 1503, Ivan III was able to push westward, and Moscow state tripled in size under his rule.
The reign of the tsars started officially with Ivan IV of Russia (Ivan the Terrible), the first monarch to be crowned Tsar of Russia, but in practice it started with Ivan III, who completed centralisation of the state (traditionally known as the gathering of the Russian lands) at the same time as Louis XI did the same in France.

Ivan III
The court of the Moscow princes combined ceremonies and customs inherited from Kievan Rus with those imported from the Byzantine Empire and Golden Horde. Some traditional Russian offices, like that of tysyatsky and veche, were gradually abolished in order to consolidate power in the hands of the ruling prince. A new elaborate system of court precedence, or mestnichestvo, predicated the nobleman's rank and function on the rank and function of his ancestors and other members of his family. The highest echelon of hereditary nobles was composed of boyars. They fell into three categories:
Rurikid and Gediminid boyars, whose fathers and grandfathers were independent princelings, felt that they were kin to the grand prince and hence almost equal to him. During the times of dynastic troubles (such as the years of Ivan IV's minority), boyardom constituted an internal force which was a permanent threat to the throne. An early form of the monarch's conflict with boyarstvo was the oprichnina policy of Ivan the Terrible.
During such conflicts, Ivan, Boris Godunov, and some later monarchs felt the necessity to counterbalance the boyardom by creating a new kind of nobility, based on personal devotion to tsar and merits earned by faithful service, rather than by heredity. Later these new nobles were called dvoryans (singular: dvoryanin). The name comes from the Russian word dvor in the meaning of tsar's dvor, i.e., The Court. Hence the expression pozhalovat ko dvoru, i.e., to be called to (serve) The Court.

Rurikid princes of Upper Oka towns, Suzdal, Rostov, Yaroslavl, etc. that lived in Moscow after their hereditary principalities had been incorporated into Muscovy (e.g., Shuisky, Vorotynsky, Repnin, Romodanovsky);
Foreign princes from Lithuania and Golden Horde, claiming descent either from Grand Duke Gediminas or from Genghis Khan (e.g., Belsky, Mstislavsky, Galitzine, Trubetskoy);
Ancient families of Moscow nobility that have been recorded in the service of Grand Dukes from the 14th century (e.g., Romanov, Godunov, Sheremetev). Assessment

List of Russian rulers
Tsardom of Moscow