ENThe author presents the names of the tribes who inhabited the major part of the coast of the Baltic Sea. At the end of the 19th century the terms Latvians, as well as Lithuanians and the Lithuanian tribes were used in the linguistic sources. Some authors called these tribes Lithuanian- Latvian (litu-lettisch). G. H. Nesselman (in his work dated 1845) used the term Balts, which became the most popular. Lithuanian linguists Kazimieras Jaunius and Kazimieras Būga used the term ‘Aesti’ following the work of Tacitus ‘Germania' who called these tribes ‘Aestorium gentes’. The author analyses ancient historical sources of Herodotus, Euripides, Pytheas, Tacitus, Ptolemy, Jordan and others. They present descriptions of the journeys by the Baltic Sea and the encounters with local inhabitants. These sources were of interest among scholars from different countries, thus the author of the article presents their interpretations as well as conclusions.