Following the devastation of Tver and Alexander's flight, Iurii's younger brother Ivan Kalita, Prince of Moscow, obtained the position of grand prince, which he held from 1328, or according to another opinion from 1332, until his death in 1341. Ivan Kalita means "John the Moneybag," and Ivan I remains the prototype of provident Moscow princes with their financial and administrative talents. Always careful to cultivate the Golden Horde, he not only retained the office of grand prince, but also received the commission of gathering tribute for the khan from other Russian princes. He used his increasing revenue to purchase more land: both entire appanages from bankrupt rulers and separate villages. The princedom of Vladimir, which he held as grand prince, he simply added to his own principality, keeping the capital in Moscow. He ransomed Russian prisoners from the Mongols to settle them on Muscovite lands. All in all, Ivan Kalita managed to increase the territory of his princedom severalfold.
It was also in Ivan Kalita's reign that Moscow became the religious capital of Russia. After the collapse of Kiev, and in line with the general breakup of unity in the land, no ecclesiastical center immediately emerged to replace Kiev, "the cradle of Christianity in Russia." In 1326 the head of the Russian Church, Metropolitan Peter, died while staying in Moscow. He came to be worshipped as a saint and canonized, his shrine bringing a measure of sanctity to Moscow. Moreover, in 1328 Ivan Kalita persuaded Peter's successor, Theognost, to settle in Moscow. From that time on, the metropolitans "of Kiev and all Russia" - a title which they retained until the mid-fifteenth century - added immeasurably to the importance and prestige of the upstart principality and its rulers. Indeed, the presence of the metropolitan not only made Moscow the spiritual center of Russia, but, as we shall see, it also proved time and again to be helpful to the princedom in diverse material matters.
Following the passing of Ivan Kalita in 1341, his son Simeon, surnamed the Proud, was confirmed as grand prince by the khan of the Golden Horde. Simeon's appellation, his references to himself as prince "of all Russia," and his entire bearing indicated the new significance of Moscow. In addition to emphasizing his authority over other Russian rulers, Simeon the Proud
continued his predecessor's work of enlarging the Muscovite domain proper. He died in 1353 at the age of thirty-six, apparently of the plague which had been devastating most of Europe. In his testament Simeon the Proud urged his heirs to obey a remarkable Russian cleric, Alexis, who was to become one of the most celebrated Muscovite metropolitans.
Alexis, in fact, proceeded to play a leading role in the affairs of the Muscovite state both during the reign of Simeon the Proud's weak brother and successor, Ivan the Meek, which lasted from 1353 to 1359, and during the minority of Ivan's son Grand Prince Dmitrii. Besides overseeing the management of affairs in Moscow and treating with other Russian princes, the metropolitan traveled repeatedly to the Golden Horde to deal with the Mongols. Alexis's wise leadership of Church and State contributed to his enshrinement as one of the leading figures in the Muscovite pantheon of saints. During Ivan II's reign, beginning with 1357, civil strife erupted in the Golden Horde: no fewer than twenty rulers were to change in bloody struggle in the next twenty years. Yet, if Mongol power declined, that of Lithuania, led by Olgerd, grew; and the Moscow princes had to turn increasing attention to the defense of their western frontier.
Ivan the Meek's death resulted in a contest for the office of grand prince, with Prince Dmitrii of Suzdal and Ivan's nine-year-old son Dmitrii as the protagonists. In a sense, the new crisis represented a revival of old Kievan political strife between "uncles'" and "nephews": Dmitrii of Suzdal, who, as well as Dmitrii of Moscow, was descended directly from Vsevolod III, was a generation older than the Muscovite prince and claimed seniority over him. Rapidly changing Mongol authorities endorsed both candidates. The rally of the people of Moscow behind their boy-ruler and the principle of direct succession from father to son carried the day: Dmitrii of Suzdal abandoned his headquarters in Vladimir without a fight, and Ivan the Meek's son became firmly established as the Russian grand prince. The Kievan system of succession failed to find sufficient support in the northeast.
Grand Prince Dmitrii, known as Dmitrii Donskoi, that is, of the Don, after his celebrated victory over the Mongols near that river, reigned in Moscow for three decades until his death in 1389. The early part of his reign, with Metropolitan Alexis playing a major role in the government, saw a continuing growth of Muscovite territory, while in Moscow itself in 1367 stone walls replaced wooden walls in the Kremlin. It also witnessed a bitter struggle against Tver supported by Lithuania. Indeed Prince Michael of Tver obtained from the Golden Horde the title of grand prince and, together with the Lithuanians, tried to destroy his Muscovite rival. Twice, in 1368 and 1372, Olgerd of Lithuania reached Moscow and devastated its environs, although he could not capture the fortified town itself. Dmitrii managed to blunt the Lithuanian offensive and make peace
with Lithuania, after which he defeated Tver and made Michael recognize him as grand prince. Muscovite troops also scored victories over Riazan and over the Volga Bulgars, who paid tribute to the Golden Horde.
But Dmitrii's fame rests on his victorious war with the Golden Horde itself. As Moscow grew and as civil strife swept through the Golden Horde, the Mongol hegemony in Russia experienced its first serious challenge since the time of the invasion. We have seen that Dmitrii had successfully defied the Mongol decision to make Michael of Tver grand prince and had defeated the Volga Bulgars, whose principality was a vassal state of the Golden Horde. A series of incidents and clashes involving the Russians and the Mongols culminated, in 1378, in Dmitrii's victory over a Mongol army on the banks of the Vozha river. Clearly the Mongols had either to reassert their mastery over Moscow or give up their dominion in Russia. A period of relative stability in the Golden Horde enabled the Mongol military leader and strong man, Marnai, to mount a major effort against Dmitrii.
The Mongols made an alliance with Lithuania, and Marnai set out with some 200,000 troops to meet in the upper Don area with forces of Grand Prince Jagiello of Lithuania for a joint invasion of Muscovite lands. Dmitrii, however, decided to seize the initiative and crossed the Don with an army of about 150,000 men, seeking to engage the Mongols before the Lithuanians arrived. The decisive battle, known as the battle of Kulikovo field, was fought on the eighth of September 1380 where the Nepriadva river flows into the Don, on a hilly terrain intersected by streams which the Russians selected to limit the effectiveness of the Mongol cavalry. The terrain was such that the Mongols could not simply envelop Russian positions, but had to break through them. Fighting of desperate ferocity - Dmitrii himself, according to one source, was knocked unconscious in combat and found after the battle in a pile of dead bodies - ended in a complete rout of Mamai's army when the last Russian reserve came out of ambush in a forest upon the exhausted and unsuspecting Mongols. Jagiello, whose Lithuanian forces failed to reach Kulikovo by some two days, chose not to fight Dmitrii alone and turned back. The great victory of the Russians laid to rest the belief in Mongol invincibility. What is more, the new victor of the Don rose suddenly as the champion of all the Russians against the hated Mongol oppressors. While certain important Russian rulers failed to support Dmitrii, and those of Riazan even negotiated with the Mongols, some twenty princes rallied against the common enemy in an undertaking blessed by the Church and bearing some marks of a crusade. The logic of events pointed beyond the developments of 1380 to a new role in Russian history for both the principality and prince of Moscow.