There were many points of difference between these invaders and the Goths. The Lombards had had little intercourse with the Empire, and were far less civilized than their predecessors, and far inferior in both military and administrative capacity. Their leader, Alboin, cannot be compared in any respect with Theodoric. Moreover, Theodoric came, nominally at least, as lieutenant of the Emperor, and affected to deem his sovereignty the continuation of Imperial rule; whereas the Lombards regarded only the title of the sword and invariably fought the Empire as an enemy. The invaders met little active resistance; if they had had control of the sea, they would readily have conquered the whole peninsula. They overran the North and strips of territory down the centre within a few years, and afterwards gradually spread little by little; but they never conquered the South, the duchy of Rome, or the Adriatic coast. For the greater part of the two hundred years during which the Lombard dominion existed, the map of Italy bore the following aspect: the Empire retained the little peninsula of Istria; the long strip of coast from the lowlands of Venetia to Ancona, protected by its maritime cities, Ravenna, Rimini, Pesaro, Sinigaglia; and the duchy of Rome, which spread along the Tyrrhene shore from Civita Vecchia to Gaeta; Naples and Amalfi; the territories of the heel and toe; and also Sicily and Sardinia. The boundaries were never fixed. Of the Lombard kingdom all one need remember is that it was a loose confederation of three dozen duchies; and that of these duchies, Spoleto, a little north of Rome, and Benevento, a little northeast of Naples, were the most important, as well as the most detached from the kingdom. In fact, these two were independent duchies, and rarely if ever took commands from Pavia, the king's capital, except upon compulsion.