text: Early modern age The earliest theorization about Chakavian originates in the 19th century nation-building and romantic nationalism. At the time the widespread belief was that individual ethnic nation must be historically characterized and identified with a specific language (which was argued pseudo-scientifically according interrogatory pronouns, yat reflex, and various historiographical theories usually related to De Administrando Imperio from the 10th century). In the beginning of the debate, as Chakavian did not exist yet, Kajkavian was identified with the Croats and Shtokavian with the Serbs (with Shtokavian-speaking Croats considered as "Catholic Serbs"). As soon as theorization about Chakavian began, early Slavists such as Josef Dobrovský, Pavel Jozef Šafárik, Jernej Kopitar, Vuk Karadžić grouped Chakavian with Shtokavian, but as Shtokavian was perceived as an exclusively Serbian language, the Croats were reduced to merely a toponym (or Chakavian and Shtokavian-speaking "Catholic Serbs"). At the time were also coined terms such as "Slavic-Serbian" and "Serbo-Croatian" language. With new insights by the mid-19th century, Chakavian was considered to be the only and original language of Croats, while Kajkavian was related to the Slovenes, and Shtokavian continued to be related with the Serbs (per Vuk Karadžić etc.). Others however, like August Leskien, continued to advance the older opinion until the late 19th century. The basic premise was that with the Ottoman invasion most of Croatia lost its native ethnic Croatian population because the presumed borders of the Chakavian speakers were reduced, and they therefore became ethnically Serbian. Some believed that Kajkavian-speaking Croats took over Serbian (Shtokavian-Chakavian) literary language. Such, more political than scientific misconceptions were present both on the Serbian and Croatian sides and internationally, and continue to plague the public and less scientific viewpoint and understanding of the Serbo-Croatian dialects, being among pivotal points of legitimacy for the 20th century nationalist revisionism and pretensions (including the recent 1990s Yugoslav Wars). The terms of Chakavian and Shtokavian dialect were introduced to Croatian linguistics by Antun Mažuranić and Vjekoslav Babukić in the mid-19th century.