The Baltic states (also known as the Baltics, Baltic nations or Baltic countries; ,) are three northern European countries east of the Baltic Sea – Estonia, Latvia and Lithuania. Baltic States co-operate on regional level in several intergovernmental organizations.
While the indigenous populations of Latvia and Lithuania are known as Baltic peoples, those of Estonia are Finnic peoples. Another Baltic identity, Baltic German, began to develop during the Middle Ages after the Livonian Crusade.
Linguistic and historical considerations intersect in defining the concept of "Baltic states": for example, while Latvian is phylogenetically related to Lithuanian (both belonging to the Baltic group of the Indo-European language family) Estonian belongs to a completely different family – the Uralic languages. At the same time, despite considerable linguistic proximity, politically Latvia and Lithuania have gone different ways for most of their history, Lithuania at one point forming a commonwealth with Poland, giving rise to one of the largest countries in Europe at the time; while Latvia has shared most of its history with Estonia, both being governed by a Baltic German élite for more than 700 years. The Livonians (a nearly extinct ethnic group closely related to Estonians) have also participated in the ethnogenesis of Latvians: according to most accounts, the assimilation of (Uralic) Livonians by ancient (Indo-European) Baltic tribes formed the basis of what are today known as the Latvian language and Latvians.