The relationship between the Popes and the Kings and Queens of Europe was complex and varied over time. In the Middle Ages, the Pope was seen as the highest authority in Europe and had the power to crown kings and queens. This gave the Pope a great deal of influence over the rulers of Europe, and the Pope could even excommunicate rulers who disobeyed him. In later centuries, the power of the Pope diminished, but the relationship between the Pope and the rulers of Europe remained important. For example, in the 19th century, Pope Pius IX was a major influence in the unification of Italy.
