Although the concepts of pre-Christian Baltic religion have not been systematized, they can be reconstructed using several sources that contain pre-Christian elements. These sources include: artifacts found in archaeological digs; folklore texts, in particular Latvian and Lithuanian formulaic folk songs, riddles, and magic incantations; written texts, such as medieval chronicles; records of witch trials from the sixteenth century to the first half of the eighteenth century; church visitation records; written accounts of travelers; geographical descriptions of the Baltic territories; and archaic elements retained in language, in particular in toponyms and hydronyms.

The earliest written records that provide information about the Baltic pre-Christian religion are found in Germania 45, written during the first century CE by the Roman historian Publius Cornelius Tacitus, who mentions that the Aestii, a term coined by him to refer to the "people of the East," worshiped the mother of God (Lat...