However, the most important factor for Moscow to develop into a national form is a series of ambitious, powerful and lucky princes and rulers. Daniil Alexandrovich Granin, the first ruler of Moscow Principality, is the youngest son of alexander nevsky of Novgorod Principality. He seized Kolomna and inherited Pereslav-Zaleski, thus expanding the territory of the Principality. Daniel's son, Yuri of Moscow, controlled the whole moscow river Valley and spread westward to Moskovski. Later, he made an alliance with the moon of the Mongolian Golden Horde, the master of the Russian princes, married Khan's sister, and immediately called himself Grand Duke Novgorod, allowing him to interfere in the affairs of the Republic of Novgorod.
Yuri's successor Ivan I (1325- 1340 reigned) maintained a good relationship with the Golden Horde, and obtained the title of Grand Duke Vladimir, thus having the right to collect tributes and taxes from other Russian principalities. The relationship with the Golden Horde also provided opportunities for Ivan's expansion, especially for Tver in the north, which rebelled against Mongolian rule in 1327. The rebellion was jointly suppressed by the Golden Horde and Moscow. Ivan I is regarded as the richest man in contemporary Ross. He was named "Kalita" (meaning "purse"). He used his wealth to buy more territory from other principalities and supported the construction of the Moscow Kremlin. 1327, Bishop Peter of the Orthodox Church moved from Kiev to Moscow, further enhancing the prestige of this new principality. Ivan's heirs constantly seized the territory, population and wealth of Moscow Principality. In the process of expansion, it is inevitable that there will be conflicts of interest with the Grand Duchy of Lithuania in the west. Lithuanians are eager to overwhelm the Eastern Slavs and their Orthodox Church. Lithuanian Grand Duke Algirdas married Tver and formed an alliance. He made three expeditions to Moscow on 1368, 1370 and 1372, but failed to capture the city. Smolensk, a city between Moscow and Vilnius, became the focus of contention between the two sides.
During the period of 1348- 1349, the country and the royal family were severely hit by the Black Death. Dmitry Ivanovich's parents died when he was nine years old, and the position of Dagong fell to his distant relative suzdal's Dmitry. Surrounded by pagans and Muslim tribes in the Grand Duchy of Lithuania, Dmitry decided to form an alliance with the Russian Orthodox Church. At that time, the Russian Orthodox Church gradually grew because of the reform of Saint Sergius in Radonezh.
Under the guidance and influence of Bishop alex Toto, Dmitry claimed to be the protector of the Orthodox Church and had the mission of uniting the Russian kingdoms against the Golden Account khanate in the melee. He challenged Jin Zhanghan's authority and defeated Mamehan's army in the Battle of Kulikovo in 1380. Although the victory of this war was offset by the defeat of the expedition a few years later, he succeeded in whitewashing the image that the Principality of Moscow had been flattering the Mongols. 1389, Dmitri passed on the position of Dagong to his son Vasily I without Kim's permission.