But the fact that there were two different heirs to the Roman tradition placed the faithful burghers of the Middle Ages in a difficult position. The theory behind the mediæval political system was both sound and simple. While the worldly master (the emperor) looked after the physical well-being of his subjects, the spiritual master (the Pope) guarded their souls.
In practice, however, the system worked very badly. The Emperor invariably tried to interfere with the affairs of the church and the Pope retaliated and told the Emperor how he should rule his domains. Then they told each other to mind their own business in very unceremonious language and the inevitable end was war.
Under those circumstances, what were the people to do? A good Christian obeyed both the Pope and his King. But the Pope and the Emperor were enemies. Which side should a dutiful subject and an equally dutiful Christian take?
It was never easy to give the correct answer. When the Emperor happened to be a man of energy and was sufficiently well provided with money to organise an army, he was very apt to cross the Alps and march on Rome, besiege the Pope in his own palace if need be, and force His Holiness to obey the imperial instructions or suffer the consequences.
But more frequently the Pope was the stronger. Then the Emperor or the King together with all his subjects was excommunicated. This meant that all churches were closed, that no one could be baptised, that no dying man could be given absolution--in short, that half of the functions of mediæval government came to an end.
More than that, the people were absolved from their oath of loyalty to their sovereign and were urged to rebel against their master. But if they followed this advice of the distant Pope and were caught, they were hanged by their near-by Liege Lord and that too was very unpleasant.
Indeed, the poor fellows were in a difficult position and none fared worse than those who lived during the latter half of the eleventh century, when the Emperor Henry IV of Germany and Pope Gregory VII fought a two-round battle which decided nothing and upset the peace of Europe for almost fifty years.
In the middle of the eleventh century there had been a strong movement for reform in the church. The election of the Popes, thus far, had been a most irregular affair. It was to the advantage of the Holy Roman Emperors to have a well-disposed priest elected to the Holy See. They frequently came to Rome at the time of election and used their influence for the benefit of one of their friends.