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. 

The Thirty Years' War erupted when the Peace of Augsburg (1555) no longer seemed to be sufficient to keep the peace in the various German states; the growth of Calvinism, which was not accounted for in the previous treaty, further threatened the status quo. Lutheran princes formed a Protestant Union (1608), and Catholic princes formed the Catholic League (1609). Tensions came to a head in 1618, when Protestants in Bohemia threw the representatives of a Catholic king out of a window (the Defenestration of Prague). The war lasted for thirty years, with both the Austrian and Spanish Hapsburgs siding with the Catholic princes.

The Edict of Nantes was issued in 1598 by the French King Henry IV. It brought to an end the French Wars of Religion, which had raged violently for almost forty years. The Edict extended religious tolerance to Calvinists (known as Huguenots) within the Kingdom of France, although they were still persecuted on both a state and local level on a frequent basis. The Edict was revoked in 1685 by King Louis XIV, who issued the Edict of Fontainebleau. The Edict of Nantes can also be understood as an extension of the Edict of St. Germain, which was issued by Catherine de Medici during the period of time when she reigned as regent of the French Kingdom. The Edict of St. Germain allowed for French Calvinists to worship privately, but was widely ignored and came at the height of tensions between the Catholic and Protestant populations, tensions that would very soon break out into civil war through the French Wars of Religion.

The Peace of Utrecht ended the War of Spanish Succession (1701-1714). The War of Spanish Succession broke out when King Charles II, the last Hapsburg monarch of Spain, died childless and without a clear legitimate heir to the throne. It was Charles’ wish that the throne, and the entire Spanish colonial inheritance, be left to Philip, Duke of Anjou, who just so happened to be the grandson of the French King Louis XIV. During this time period, the Kingdom of France was growing dramatically in power and influence, and the idea of a Kingdom of France and Spain, with all their overseas holdings, all under the dominion of King Louis XIV, troubled the other ruling princes of Europe, who were worried that France would become a hegemonic power and upset the balance of power in Europe. The Peace of Utrecht allowed Philip to inherit the Spanish throne on the condition that he renounce any future claims to being King of France.

The Treaty of Aix-la-Chapelle was signed in 1748 and brought to an end the hostilities of the Austrian War of Succession. The Treaty was understood, even at the time, as little more than a truce, particularly between France and Great Britain, as it settled few of their disputes over North America, Europe, and the Indian subcontinent. These issues would reemerge only six years later with the outbreak of the Seven Years’ War.

The Congress of Vienna convened in 1815 to decide how to divide Europe among the major European powers in the wake of the Napoleonic Wars. All of these representatives are correctly matched except for Prince Metternich, who was the Austrian diplomatic representative. Prussia was represented by Karl von Hardenberg.

The Pragmatic Sanction of 1713 was issued by the Hapsburg ruler Charles VI to ensure that in the event of there being no legitimate male heir, his throne and the various inheritances of the Hapsburgs would pass to his eldest daughter Maria Theresa. Prior to the Pragmatic Sanction, ancient German law prevented a daughter from inheriting lands and titles from her father. Charles VI did indeed die without leaving a legitimate male hair and Maria Theresa did succeed him as ruler of Austria and the diverse Hapsburg lands, but her accession nonetheless resulted in the outbreak of conflict in 1740 with the War of Austrian Succession.