George William, also known as George IV William was the last Silesian duke of Legnica (Liegnitz) and Brzeg (Brieg) from 1672 until his death. He was the last male member of the Silesian Piast dynasty descending from Władysław II the Exile (1105–1159), as well as the last legitimate male member of the entire House of Piast.

The Duke of Silesia was the title of sons and descendants of the Polish Duke Bolesław III Wrymouth. In accordance with the last will and testament of Bolesław, upon his death his lands were divided into four or five hereditary provinces distributed among his sons, and a royal province of Kraków reserved for the eldest, who was to be High Duke of all Poland. This was known as the fragmentation of Poland. Subsequent developments lead to further splintering of the duchies.