Kazlų Rūda Forest (), is in Suvalkija, but is located on sandy soil unsuitable for farming. Suvalkija remains one of the most important agricultural regions of Lithuania, harvesting large crops of sugar beets. Cultural history Originally, the region was inhabited by the Baltic tribe of the Sudovians (hence the name "Sudovia"). The Teutonic Knights frequently raided the region during the Middle Ages in ongoing attempts to conquer and baptize the pagan Grand Duchy of Lithuania. As a result, most of ancient Sudovia became a sparsely-inhabited wilderness covered by large forests. After the Battle of Grunwald in 1410, which ended the crusades against Lithuania, the territory was slowly repopulated by settlers from Samogitia and Aukštaitija. They brought their cultures, which mingled with that of the remaining local Sudovians, and an ethnologically-distinct culture gradually took shape, combining Samogitian and Aukštaitian elements and indigenous elements not found anywhere else. Significant changes took place during the late 18th and early 19th centuries. Suvalkija was separated from Lithuania Proper. While the Napoleonic period was brief, it resulted in lasting impacts. Of these impacts, the most important were the introduction of the Napoleonic Code, the usage of the Gregorian Calendar, and the abolition of serfdom almost 50 years earlier than in the rest of Lithuania. Peasants gained personal freedom and opportunities to acquire wealth. The region also offered better educational opportunities to its residents – Veiveriai Teachers' Seminary and Marijampolė Gymnasium continued their operations at a time when most educational institutions in Lithuania were closed following the 1863 January Uprising against the Russian Empire. Students could also attend Roman Catholic seminaries in Sejny and Kaunas. According to the census taken in 1897, the rate of literacy among the peasants of the Suvalkai Province was the highest in the Russian Empire. The people of Suvalkija were also among the first and most numerous emigrants to the United States. These developments led to the formation of a new well-educated class, which fueled the Lithuanian National Revival in the second half of the 19th century. Among the many notable figures from the region were the patriarch of Lithuanian independence Jonas Basanavičius, Vincas Kudirka, the author of the Lithuanian nation anthem, and Jonas Jablonskis, a linguist frequently credited with the creation of a standardized Lithuanian language. Dialects spoken in Suvalkija became the basis for the modern language. The Revival, which had previously been centered in eastern Samogitia, gradually shifted to