The term "Sudeten Germans" (Sudetendeutsche) came about during rising ethnic nationalism in the early 20th century, after the fall of the Austro-Hungarian Empire in the First World War. It coincided with the rise of another new term, "the Sudetenland", which referred only to the parts of the former Kingdom of Bohemia that were inhabited predominantly by ethnic Germans. These names were derived from the Sudeten Mountains, which form the northern border of the Bohemian lands.