ENThe article discusses the significance of ethnic roots in the life of the nation and the state, presents historical sources of the insights of modern scholars about the Western Balts (Aisčiai): the Sūduvians, the Prussians and the Yotvingians. Issues of Lithuanian ethnic origin were examined in more details only in the second half of the seventies of the 20th century. Eugenijus Jovaiša, who presented a systematized, integrated and scientifically based history of Lithuanian origin, has done the most in the field of Lithuanian origin. Indo-European languages developed in different ways: some receded far slower from the pro-language, others did faster, some kept more antiquity, and others did less. Lithuanian is less distant from the pro-language than other living Indo-European languages; therefore, it contains more archaisms. That the Lithuanian language is archaic, rich and beautiful is noticed by the linguists from all over the world; therefore, it is important for the students of comparative linguistics, and is taught at many universities around the world. The similarity between the ancient Indian (Sanskrit) and Lithuanian languages is striking. Linguistic palaeontology, like archaeology and cultural history, helps to uncover complex ancient secrets.