It has been famously pointed out that the Holy Roman Empire was neither holy, nor Roman, but it was also not an empire in the sense people expect when hearing the term. In theory, the emperor was the highest prince in Christendom, and his dominion extended the length and breadth of Western Europe. The empire had been created by the papacy in 801 when Pope Leo III famously crowned the supposedly unwitting Charlemagne in Saint Peter’s Basilica, intending to recreate the Western Roman Empire.

In truth, the imperial power did not extend beyond central Europe, which by the beginning of the 16th century included Germany, northern Italy, and the Netherlands. Even in these lands, however, the emperor struggled to command obedience. His dominion over northern Italy was theoretical only, the cities of the Netherlands were deeply conscious of their ancient rights and privileges, and Germany had long ceased to be compliant. The latter had become a collection of principalities, dukedoms, and bishoprics, which vied with each other and pursued their own agendas. They were, however, united in only one sense: denying the emperor power and resisting attempts to centralize the government.

At the same time, the secular sovereigns frequently butted heads with religious authorities back in Rome, and arguably none of the conflicts were as crucial as the Investiture Controversy in the 11th century. The tensions between the Holy Roman Empire and Church over the power to invest bishops with authority led to decades of civil war in Germany on the way to establishing the relationship between Church and state, elevating the status of the papacy and weakening the Holy Roman Empire.