RTS based on the Hussites and the Hussite Wars (1419-36).
The Hussites (Czech: Husité or Kališníci; "Chalice People") were a Czech Proto-Protestant Christian movement that followed the teachings of reformer Jan Hus, who became the best known representative of the Bohemian Reformation.
The Hussite movement began in the Kingdom of Bohemia and quickly spread throughout the remaining Lands of the Bohemian Crown, including Moravia and Silesia. It also made inroads into the northern parts of the Kingdom of Hungary (now Slovakia), but was rejected and gained infamy for the plundering behavior of the Hussite soldiers.
Source: Wikipedia, "Hussites", available under the CC-BY-SA License.