A YEARNING FOR THE GLORY THAT WAS ROME It was no accident that Charlemagne tried to re-establish the Roman Empire, nor that his successors styled themselves Holy Roman Emperors. Those who ruled in medieval Europe had a yearning for both the stability and control that Rome had at the height of the Empire. Each wanted all of Europe to act in a unified fashion, but each King wanted to be in control. The Holy Roman Emperors resented the independence of the various Kings, as the the Popes, who also saw themselves as the rightful heirs of the Roman Emperors.
One thing that unified all the political leaders of Europe was preserving the access to two key needs of their people: access to the spices from the Orient, and access to the sites of religious pilgrimage. The various crusades were fought to secure these two resources. Though most of the crusades were failures in their stated goal of Christian and European control over Jerusalem, they did preserve European access to both spices and the various destinations of pilgrims for close to two centuries.