This map by Tobias Mayer (1723-62), an astronomer and professor of Mathematics from Göttingen, shows the Gulf of Finland. From 1746 to 1751, Mayer was the director of the publishing house Homann, which specialized in maps. The map shows the complete territory of the governorate of Estonia, then part of Imperial Russia. The copper engraver Johann Baptist Homann (1664-1724) had founded the publishing house in 1702. After the founder’s son had died, Johann Georg Ebersberger (1695-1724) and Johann Michael Franz (1700-1761) ran the business. The map was included in the „Atlas geographicus maior“, the most prestigious edition of this publishing house, which flourished during those years and produced a considerable number of new, high quality maps.