Jan II the Mad also known as the Bad, the Wild or the Cruel, was a Duke of Żagań-Przewóz since 1439, from 1449 Duke of Przewóz, during 1461–1468 and briefly in 1472 Duke of Żagań and during 1476–1488 Duke of half-Głogów.

Żagań is a town in western Poland, on the Bóbr river, with 25,731 inhabitants (2019). The town is the capital of Żagań County in the historic region of Silesia. Previously in the Zielona Góra Voivodeship (1975–1998), Żagań has been in the Lubusz Voivodeship since 1999.