This article reviews the clothing of Catherine Jagiellon (1526–83), the Princess of Poland, Duchess of Finland (1562–1583), Grand Princess of Finland (1581–1583), and Queen of Sweden (1569–1583), in two documents which constitute the main sources for her possessions. The first document was written in connection with Catherine’s wedding with Duke John of Finland in Vilnius in 1562 as an inventory of her dowry, the second one in Stockholm in 1563 to list Catherine and her husband’s property. The inventory of dowry, written in Polish, has not been fully or at all used by researchers in Western Europe prior to this study, and the inventory of possessions, written in Swedish, has not been known to researchers in Eastern Europe. Therefore, previous research on the subject has not been able to make use of the available data in its entirety. However, by analysis and comparison of the entries in the two documents, it has been possible to complete the previously imprecise picture of the Renaissance princess’s wardrobe, as well as to reveal the changing customs of dressing oneself in changing surroundings.