Frederick I was the last Duke of Prussia and the first King of Prussia. Due to the ever-expanding size and power of Prussia he felt simply being a Duchy no longer reflected the importance of Prussia. As such an upgrade to a Kingdom was ordered.

The Edict of Nantes was signed by Henry IV of France in 1598. This consolation to the French Protestants was meant to give them religious freedom and thus put an end to the French Wars of Religion.

Following the death of Sigismund II and the end of the Piast Dynasty, Poland transitioned to an elected monarchy. This was because in the final decree of Sigismund he determined that this would be the best form of government for the nation rather than finding a single new royal family. In this system a noble would be elected by a vote of all noble families to rule for life.

By 1700 when Philip of France was named by Charles II of Spain as his successor, Europe had fallen into a delicate balance of power. Austria, Prussia, France, Spain, and England were all independent nations that were powerful enough to balance each other out so that no one nation could conquer the others. However, if France and Spain were now one royal family, combined, their armies could take on the might of any of these nations and win, thus causing the balance of power to swing in the favor of France.

The French Revolution officially ended when Napoleon crowned himself Emperor of France in 1804. This put an end to 15 years of chaos in France at the hands of a revolving door of leadership. The French Government had gone through the hands of dozens of men, most of whom were run out of the country or killed by rivals seeking to fill the power vacuum left by the French Monarchy.

1804-1814 is considered the apogee of Napoleon's political power and authority as Emperor of France. He would be unchallenged as French ruler until after his abdication and exile to Elba in 1814-1815. Both Robespierre and Louis XVI were executed long before 1804. Finally, neither anarchy or a foreign army would rule France entirely, and never at all for more than a year.

During the Renaissance, Italy consisted of five main city-states: Venice, Milan, Florence, the Papal States, and the Kingdom of Naples, each with its own system of government. There were struggles for power among these various political entities, and their internal and external struggles made Italy vulnerable to invasion.  Continental powers (notably the French and Austrians under Charles V) fought for territorial control in Italy in the late fifteenth and sixteenth centuries. 

In the wake of the Protestant reformation, some German princes embraced Lutheranism for myriad reasons, which increased political division within the German states of the Holy Roman Empire. Charles V and the French Valois dynasty went to war repeatedly throughout the sixteenth century, and much of the fighting took place in Germany. The French kings tended to support Lutheran princes to promote disunity and defy Charles V. Eventually, Charles V accepted the Peace of Augsburg, which recognized Lutheranism and permitted German princes to choose whether their states would be Catholic or Lutheran.

The Peace of Westphalia marked the end of the Thirty Years' War in 1648.  In Germany, it reinforced the previous stipulations of the Peace of Augsuburg, with the addition that Calvinism was also permissible. The northern German states were largely Protestant; the southern German states were Catholic.

Neville Chamberlain was Prime Minister of the United Kingdom from 1937 to 1940. He tried to maintain peace for his people, as the British were still weary from World War I. The strategy of appeasement had been used on Hitler since 1935, but the most notable measure of it was granting the Sudetenland, part of Czechoslovakia which had a large German population, to Germany, which Chamberlain agreed to in 1938. Hitler then conquered the rest of Czechoslovakia, which outraged Britain and France, but there was little else they could do at that point. When Hitler threatened to invade Poland, he was warned that it would mean war, and upon his invasion in 1939, Britain and France declared war on Germany.