The Grand Duchy of Lithuania was a European state that lasted from the 13th century to 1795, when the territory was partitioned among the Russian Empire, the Kingdom of Prussia, and the Habsburg Empire of Austria. The state was founded by Lithuanians, who were at the time a polytheistic nation born from several united Baltic tribes from Aukštaitija.
The Grand Duchy expanded to include large portions of the former Kievan Rus' and other neighbouring states, including what is now Belarus and parts of Ukraine, Latvia, Poland, Russia and Moldova. At its greatest extent, in the 15th century, it was the largest state in Europe. It was a multi-ethnic and multi-confessional state, with great diversity in languages, religion, and cultural heritage.
The consolidation of the Lithuanian lands began in the late 12th century. Mindaugas, the first ruler of the Grand Duchy, was crowned as Catholic King of Lithuania in 1253. The pagan state was targeted in the religious crusade by the Teutonic Knights and the Livonian Order. The rapid territorial expansion started at the late reign of Gediminas and continued to expand under the diarchy and co-leadership of his sons Algirdas and Kęstutis.