Sigismund is a common name.

Sigismund of Burgundy (Saint Sigismund), king

Sigismund, Holy Roman Emperor, also king of Luxembourg and of Hungary

Sigismund of Austria

Sigismund of Bavaria

Sigismund I the Old, King of Poland-Lithuania (1506-1548)

Sigismund II Augustus, King of Poland-Lithuania (1548-1572)

Sigismund I/III Vasa, King of Sweden as Sigismund I(1592-1599), King of Poland-Lithuania as Sigismund III (1587-1632).

Sigismund Bathory, prince of Transylvania

The name of Siegmund, a focal character in Wagner's Die Walküre, may be related to this name.