Vienna, Austria.
Vienna was the capital city of the former Holy Roman Empire, and later the capital of the former Austrian Empire. At the height of the Austrian Empire, Vienna was the largest German-speaking city in Europe.
Vienna was founded in 15 BCE as a Roman frontier settlement called Vindobona which was raised to the status of a munucipium in 212. A fire early in the fifth century destroyed much of the original Roman muncipium, although the site was not completely abandoned. Austria was organized as a border region of the Duchy of Bavaria after the defeat of the Magyars in 955, with the ruins of Roman Vindobona in its eastern reaches.
As the ruling Babenburg family expanded Austria across the Danube, Vienna revived as a center of trade. Austria was detached from Bavaria and made a separate duchy by the Holy Roman Emperor Frederick Barbarossa in 1156, and the new Duke Henry II established his capital at Vienna. Austria passed into the control of the Habsburgs, a Swiss noble family, in 1278, and they kept Vienna as their capital. When Duke Albert V of Austria was elected Holy Roman Emperor in 1438, Vienna became the capital of the empire.
The fall of Constantinople to the Ottoman Turks in 1453 led to the rapid expansion of Ottoman rule in the Balkans, and two major Turkish sieges of Vienna took place in 1529 and 1683, both unsuccessful. After the second siege, the power of the Ottoman Empire began to diminish, and the Austrians were able to extend their control into the Balkans. A series of dynastic marriages in the late fifteenth and sixteenth centuries brought the Habsburgs to power in the Netherlands, southern Italy, and Spain. However, the Emperor Charles V found the empire he had inherited too unwieldy to rule, and he divided his domains between his son Philip and his younger brother Ferdinand. It was Ferdinand who succeeded to the rule of Austria and the Holy Roman Empire, and his descendants continued to rule Austria for the rest of its existence.
The Habsburg monarchy's fortunes began to decline in the eighteenth century, when a series of wars with the Kingdom of Prussia led to the permanent loss of Silesia to Prussia. The last of these wars, known as the Habsburg War of 1795 to 1799, led to the final collapse of the Holy Roman Empire, and the creation of the Germanic Confederation, which was led by Prussia and which excluded the Habsburg domains. When a wave of revolutionary chaos called the Bloody Eighties spread across Europe in the early 1880s, Vienna was particularly hard hit, suffing extensive looting and a great deal of property damage. As a result, standards of living in the Austrian Empire were the worst in Europe. The collapse of the Austrian Empire in the early twentieth century marked the end of Vienna as an imperial capital.