Tsar Alexis, also known as Alexis I of Russia, ruled from 1645 to 1676. He was the second Romanov tsar and is known for his efforts to modernize Russia and strengthen its central authority. His reign saw the expansion of Russian territory and the establishment of a more organized government. During Alexis's rule, significant social and economic changes occurred, including the introduction of new agricultural practices. He also faced challenges such as the Time of Troubles and conflicts with neighboring countries. Alexis's policies laid the groundwork for future reforms under his son, Peter the Great.