The Grand Duchy of Tver was a historical principality in northeastern Russia, established in the late 13th century. It emerged as a significant political entity during the period of the Mongol invasion and was known for its rivalry with the neighboring Grand Duchy of Moscow. Tver played a crucial role in the development of Russian statehood and culture. At its height, the Grand Duchy of Tver encompassed a large territory, including parts of modern-day Tver Oblast. The capital, also named Tver, became an important center for trade and governance. The duchy eventually lost its independence in the late 15th century, becoming part of the expanding Moscow state.