58. We have no space to speak of the immediate successors of Otto the Great.[102] Like him they had to meet opposition at home as well as the attacks of their restless neighbors, especially the Slavs. The Empire is usually considered to have reached its height under Conrad II (1024-1039) and Henry III (1039-1056), the first two representatives of the new Franconian line which succeeded the Saxon house upon its extinction in 1024. [Sidenote: Conrad II, 1024-1039.] [Sidenote: Poland.] By an amicable arrangement the kingdom of Burgundy came into the hands of Conrad II in 1032. This large and important territory long remained a part of the Empire, serving to render intercourse between Germany and Italy easier, and forming a barrier between Germany and France. On the eastern borders of the Empire the Slavs had organized the kingdom of Poland in the latter half of the tenth century, and its kings, although often at war with the emperor, generally acknowledged his suzerainty. Conrad, following the policy of Otto the Great, endeavored to bring as many of the stem duchies as possible into the hands of his son and successor, Henry III, who was made duke of Franconia, Swabia, and Bavaria. This was the firmest of all foundations for the kingly power. [Sidenote: Henry III, 1039-1056.] Notwithstanding the energy and ability of Conrad II and Henry III, the fact that the Empire stands forth as the great power of western Europe during the first half of the eleventh century is largely due to the absence of any strong rivals. The French kings had not yet overcome the feudal disruption, and although Italy objected to the control of the emperor, it never could agree to combine against him. [Sidenote: Henry III and the Church.] 59. The most important question that Henry III had to face was that of a great reform of the Church. This was already under way and it was bound, if carried out, to destroy the control of the emperors not only over the papacy but also over the German bishops and abbots, whom they had strengthened by grants of land and authority with the special purpose of making them the chief support of the monarchy. The reform was not directed particularly against the emperor, but he was, as will become apparent, more seriously affected by the changes proposed by the reforming party than any other of the European rulers. [Sidenote: Wealth of the Church.]