Ivan I "Kalita" was the son of Prince
Daniel of
Moscow, and became Grand Prince of
Russia in 1328 when his cousin
Alexander fled the country to avoid a combined
Mongol/
Moscow army coming to punish him for the death of a Mongol envoy in the city of Tver. Ivan's
nickname "Kalita" is usually translated as "
Moneybags"; he tended to accumulate money by any means necessary and consider it the source of his power. (Given that his older brother
Yuri III was once passed over as Grand Prince because rival
Mikhail gave the Mongol Khan more gifts, this was a fairly logical point of view to have.) Ivan used the money to buy
land from the local princes who were nearly broke, so that he could add it to the domain controlled by Moscow; he increased the size of Moscow's lands by several hundred percent.
During Ivan's reign, he had to fight off many Lithuanian attacks from the northwest, and also deal with the general rebelliousness of many Russian cities, most notably Novgorod and Smolensk. The cities were mostly tired of the heavy taxes imposed by the Mongols and collected by Ivan (with some extra demands for himself added, usually). Nonetheless, Ivan managed to keep control of the rebellious cities, and on the death of his predecessor Alexander of Tver, he even sent an expedition to take possession of Tver and bring back the big bell which hung in its civic building to Moscow, as a symbol of the subjection of Tver to Moscow.
During Ivan's reign the Russian Orthodox Church also left its former central headquarters in Kiev. This was an accident at first; Russian church leader Metropolitan Peter died while on a visit to Moscow in 1326; a shrine was built to him there. Ivan persuaded the next Metropolitan, Theognost, to settle in Moscow permanently, enhancing Moscow's prestige. Ivan died in 1341 and left to his son Simeon a claim to the Grand Prince's title that was much firmer than Ivan had had.