http://www.ngw.nl/heraldrywiki/index.php?title=Estate_of_Windischen_Mark Estate of Windischen Mark - Heraldry of the World
Origin/meaning
The Estate of the Windischen Mark (now part of Slovenia) became a possession of the Habsburg dynasty already in 1282. The arms show a typical hat for the area, and are thus considered canting. The arms were probably devised under the reign of Duke Rudolf IV of Austria (around 1350).
Literature : Ströhl, 1890

http://de.wikipedia.org/wiki/Windische_Mark
http://en.wikipedia.org/wiki/Windic_March
The Windic March (German: Windische Mark; Slovene: Slovenska marka or Slovenska krajina) was a medieval frontier march of the Holy Roman Empire, roughly corresponding to the Lower Carniola (Dolenjska) region in present-day Slovenia.