The paper is devoted to a source essential for the Karelian language – hand-written Karelian-Russian lexical notes dated to the 17th century, discovered in the Solovetsky Monastery library late in the 19th century. Although previously analysed by J. Mikkola and N. Meshchersky, the source still holds much potential for studies. The paper specifies the time of writing and the author of the notes – Archimandrite Theophanes of Athos, who was held prisoner in the Solovetsky Monastery in 1666–1668. Some circumstances in which the list was produced have been disclosed. A new way to read some words in both the Russian and Karelian parts of the manuscript is suggested. The linguistic traits that allow to verify the Karelian dialect basis of the list and thus describe some characteristic features of the 17th century Karelian language in Pomorje have been identified.