Among the Italian cities, Venice, at the extremity of the Adriatic, Ravenna, at the south of the mouth of the Po, Genoa, at the foot of the Ligurian mountains, Pisa, towards the mouths of the Arno, Rome, Gaëta, Naples, Amalphi, and Bari, were either never conquered by the Lombards, or were in subjection too short a time to have lost many of their ancient habits and customs. In this way these cities naturally became the refuge of Roman civilization, at a time when other parts of Europe were wading through barbarian darkness. The feudal system never prevailed among them with any force; and several of these and other cities had important privileges conferred upon them by the German emperors at a very early period. Sismondi, the historian of Italy, asserts that Otho I (936) erected some of them into municipal communities, and permitted them the election of their own magistrates. It is certain that, in 991, the citizens of Milan rose in tumult, expelled an archbishop from their city, and were able to establish a qualified right to interfere in future elections. The after-history of Milan is eventful and tragical; but we can only give a short account of it here. In the middle of the twelfth century, Frederick Barbarossa became engaged with the cities of Lombardy, and particularly with it, in extensive and destructive wars. In the year 1162 Milan was finally overcome; the walls and houses were razed from their foundation, and the suffering inhabitants dispersed over other cities, obtaining sympathy in their distress, and communicating their enthusiastic love of freedom in return. The republican form of government was adopted in every considerable town; and before the end of the thirteenth century, there was a knowledge, a power, and an enterprise, among these apparently insignificant republics which all Europe could not match.