In this article we present an unknown map of Krakow and its surroundings with an attached description in Swedish, which is stored in the Riksarkivet, the National Archives of Sweden (Stockholm). We are scrutinizing the circumstances in which this work came into being, which indicates that the source was created between 1 and 7 October 1655, making it the oldest known map with an attached legend presenting not only Krakow, but also the adjacent towns of Kleparz and Kazimierz and the suburb of Stradom. This document was attached to an unpreserved letter that was probably sent to the Scandinavian Peninsula. We present this relic as an attempt to depict war events in an epistolographic message through a two-dimensional representation of space with a legend. We place this against the broader background of changes in worldviews at that time, shaped by increasingly popular atlases and printed maps. This work had no tactical significance, nor was it used in propaganda of the Swedish Empire. Its main purpose was to document epoch-making events. The map and legend were to complement the epistolographic message, common in correspondence of the diplomatic and military elites of the 17th century. The author must have been an educated person with considerable spatial imagination. This person’s intellectual horizons are evidenced by, among others, knowledge of the chorography of the Polish-Lithuanian Commonwealth by Szymon Starowolski (Kolonia 1632 and Gdańsk 1652). The map was presumably made by Matthias Palbitzki, a diplomat and art connoisseur.