The Duchy of Kopanica (Principality of Kopanica; Polish: Księstwo Kopanickie; German: Herzogtum Köpenick) was a Slavonic principality in Central Europe in present-day central and eastern Brandenburg. Its capital was Kopnik (German: Köpenick, today part of Berlin). The Bargello in Florence displays a sword believed to be that of Iakša de Kopnik. The Jakšić noble family of Serbia may be connected to Iakša's own clan Gryfici (Świebodzice) or their parent house the Spyra (Sperun, Pérnuš). The ducal cape found in the Eberswalde Hoard from Finów shows the eight-petaled star of Svarog, a Slavic deity.