On this day, 520 years ago, on October 27, 1505 (October 1, 1505, the founder of the centralized Russian state, Ivan III, died of illness. The work of a 19th century painter shows Ivan III refusing to pay tribute. In the 15th and 16th centuries, the Russian state gradually moved from feudal separatism to unity. In the process of realizing the historical mission of unifying the Russian state, Ivan III was a figure worth mentioning. Ivan was the second eldest son of Vasily, Grand Duke of Moscow. He was born on January 22, 1440. He was smart and cunning since childhood. Vasil II lost his eyes in the war and was a "blind archduke". When Ivan was 10 years old, he assisted his blind father in governing. In 1462, his father died and Ivan succeeded to the throne. He was known in history as "Ivan III". When Ivan III succeeded to the throne, the Grand Duchy of Moscow was already very strong through the management of his ancestors and fathers. Ivan III inherited their cause and fought to complete the reunification of the Russian state. His first goal was to annex the feudal Republic of Novgorod. The Republic of Novgorod has a vast land, abundant products, and convenient land and water transportation. It spans a corner of the northwest and has great independence. In May 1471, Ivan III held a conference in Moscow to prepare for the attack on Novgorod, calling on the princes, nobles, bishops and generals attending the conference to divide this "fat plunder." He dispatched three armies and completely defeated Novgorod at the Battle of the Seran River on July 14, forcing him to sign a treaty guaranteeing "sincere and strict support" for the archduke's rule. In 1475, Ivan III incited and used the struggle between the lower-class citizens of Novgorod against the upper-class aristocrats, and sent troops to Novgorod. In 1478, Iraq III finally eliminated the republic and incorporated its territory into the Duchy of Moscow. Soon after, the Duchy of Tver was also defeated and surrendered to the Duchy of Moscow. Later, other princes were demoted to mere local governors with little resistance. In this way, the Principality of Russia, which had been divided for more than 300 years, was basically unified under the command of Ivan III, Grand Duke of Moscow. After completing basic reunification and eliminating internal and external troubles, Ivan III carried out drastic domestic reforms. He carried out administrative reform and strengthened centralized state organs. He carried out military system reform and established a standing army of the country under his direct control. He carried out fiscal reform and unified the currency system, with the right to coinage exclusive to the Grand Duke. After he basically completed domestic reforms, he relied on his strong national strength to launch a war of external expansion. He marched into Lithuania, sent troops to the Baltic Sea coast, and marched eastward to the Tobor River, Ertysh River and Ob River basins until he died of illness on October 27, 1505. He was not only the founder of Russia's centralized state, but also the originator of tsarist Russia's external expansion. Ivan IV