The Austrian Empire was a major European power that existed from 1804 to 1867. It was formed when the Habsburg monarchy declared itself an empire, uniting various territories, including parts of modern-day Austria, Hungary, and Czech Republic. The empire was known for its diverse cultures and languages, as it included many different ethnic groups. In 1867, the empire transformed into the Austro-Hungarian Empire, granting more autonomy to Hungary. This change aimed to address rising nationalist movements within the empire. The Austrian Empire played a significant role in European politics until its dissolution after World War I in 1918.