Eastern Europe, from the coasts of the Adriatic to the limits of Mahometan conquest eastward, was subject to the emperor who reigned at Constantinople, and may, except for its incidental connection with the Crusades, be left out of the present view. The northern portions were in the hands of half-civilized, half-Christianized races, which formed a barrier dangerous but efficacious between the Byzantine emperor and Western Christendom. The kingdom of Hungary, and the acquisitions of Venice on the east of the Adriatic fenced medieval Europe from the same enemies. Italy was divided between the Normans, who governed Apulia and Sicily, and the sway of the Empire, which under Lothar II.--the Emperor who was on the throne when our period begins--had become little more than nominal south of the Alps; the independence of the imperial cities and small principalities reaching from the Alps to Rome itself was maintained chiefly by the inability of the Germans to keep either by administrative organization or by dynastic alliances a permanent hold upon it. With both the Republican north and the Normanized south, the political history of the Plantagenet kings came in constant connection; and even more close and continuous was the relation through the agency of the Church with Rome itself. At the opening of the period, Englishmen were not only studying in the universities of Italy, at Salerno, at Bologna, and at Pavia, but were repaying to Italy, in the services of prelates and statesmen, the debt which England had incurred through Lanfranc and Anselm. An Englishman was soon to be pope. The Norman kings chose ministers and prelates of English birth; and the same Norman power of organization which worked in England under Henry I. and Roger of Salisbury, worked in similar line in Sicily under King Roger and his posterity. [Sidenote: Germany.]