For the first time, scientifically Baltic languages were researched and compared with other Indo-European languages in the 19th century, when Franz Bopp in 1816 laid the ground for comparative linguistics. In his Vergleichende Grammatik, published in 1833, Lithuanian was included. Prussian language was researched by Georg Heinrich Ferdinand Nesselmann (Die Sprache der alten Preussen an ihren Ueberresten erlaeutert, 1845) and Erich Berneker (Die preussische Sprache, 1896).