James Harvey Robinson,
An Introduction to the History of Western Europe
“ With Frederick's death the mediæval empire may be said to have come to an end. It is true that after a period of "fist law," as the Germans call it, a new king, Rudolf of Hapsburg, was elected in Germany in 1273. The German kings continued to call themselves emperors. Few of them, however, took the trouble to go to Rome to be crowned by the pope. No serious effort was ever made to reconquer the Italian territory for which Otto the Great, Frederick Barbarossa, and his son and grandson had made such serious sacrifices. Germany was hopelessly divided and its king was no real king. ”
