Why isn’t Austria part of Germany?
For centuries, Austria and many other German states were part of the Holy Roman Empire, which, from the mid-15th century, was largely controlled by the Austrian Habsburgs. Later, Austria took a leading role in the German Confederation until it was defeated by Prussia. This defeat led to the establishment of the North German Confederation, excluding Austria, which eventually became the German Empire. After the Habsburg monarchy collapsed in 1918, Austria tried again to unify with Germany.