Klemens von Metternich lived over a century after the close of the Thirty Year's War, and is best known as being the Foreign Minister of the Austrian Empire and presiding over the Congress of Vienna. The Peace of Westphalia was the treaty that ended the Thirty Years' War. The Battle of White Mountain was a significant conflict in the early part of the war. Albrecht von Wallenstein was a prominent mercenary leader during the war. Gustavus Adolphus was the king of Sweden who intervened on behalf of the Protestant cause.

The Italians provided forces in excess of 50,000 land troops, and the Nazi regime tested bombing strategies and technologies during the war, as famously depicted in Picasso’s Guernica. Tens of thousands of foreign volunteers fought in the International Brigades, and Spanish anarchists resisted the fascist and conservative forces. The French Popular Front government of Leon Blum was officially neutral.

The Treaty of Brest-Livotsk was signed between the newly formed Bolshevik government of the Soviet Federated Socialist Republic (the USSR) and the Central Powers, granting the Baltic States to Germany and the Kars Oblast to the Ottomans, while also paying the Germans massive reparations. Germany’s defeat and acceptance of the Treaty of Versailles negated Brest-Livotsk. The first Battle of the Somme was an inconclusive but bloody engagement between Britain, France and Germany in Western Europe in 1916. The Battle of Tannenberg was a decisive defeat of the Russians by the German General von Hindenburg at the beginning of World War I. The Spring Offensive of 1918 was a series of advances by Germany in Western Europe using storm troopers that were ultimately reversed by American reinforcements.

When Archduke Franz Ferdinand of Austria was assassinated by Serbian radicals, Austria-Hungary declared war on Serbia. Unbeknownst to Austria, Serbia had signed a secret treaty with Russia, who had signed a secret treaty with France, who had signed a secret treaty with Britain. Austria, who had signed a secret treaty with Germany and the Ottoman Empire, prepared for war with Serbia, only to discover that it would be fighting half of Europe to do so. The diplomatic catastrophe became known as the July Crisis, as war with all European countries involved took less than a month to begin after Ferdinand's assassination June 28th 1914. 

The Reconquista was a seemingly endless conflict that permeated Spanish society. The Islamic conquests of the 8th Century pushed Catholic Spaniards into a tiny spit of land in Northern Spain. Were it not for the help from a number of other Christian nations, Catholic Spaniards would have, in all likelihood, been unable to win the conflict. Muslims were not fully ousted from Spain until 1492.

World War I was a conflict between the Allies (the United Kingdom, Russia, France, and later Japan, Italy, and the United States) and the Central Powers (primarily Germany, Austria-Hungry, and the Ottoman Empire). The Allies were formed out of the Triple Entente, which was a pact formed in 1907 between the United Kingdom, France, and Russia in order to limit political and military rivalry between those nations. Of course the war involved a variety of countries across the world and occasionally participants and alliances would change. Italy initially fought for the Central Powers until it switched sides in 1915. Russia left the war entirely due to internal political turmoil and made peace with the Central Powers. The United States did not enter the war on the side of the Allies until 1917.

At the beginning of the 20^th Century there was a lot of political and economic turmoil in Russia, due to the policies of the tsar, humiliating military defeats, and poor economic activity. This eventually led to the Russian Revolution, when the tsar was overthrown by the Bolsheviks. While this was going on Russia was involved in World War I, where it had not been faring well fighting the Central Powers. The new government wanted to remove Russia from the conflict to focus on internal issues and negotiated the Treaty of Brest-Litovsk with the Central Powers in 1918. The treaty called for Russia to forfeit some of its land and also to pay Germany for damages in exchange for peace. The terms of the treaty were essentially rendered irrelevant following the defeat of the Central Powers.

The Opium Wars were fought from 1839 to 1842 and from 1856 to 1860. The conflicts stemmed from the fact that China was imported very little from European nations until Great Britain started to sell opium to the Chinese. People became addicted to the drug and demanded more while society began to deteriorate. China outlawed opium and then attempted to cut off its foreign trade and so Great Britain took military action to ensure that trade would continue. The first war resulted in China agreeing to continue to trade with Great Britain and to open up some ports just for trade. The second war came about when Britain wanted to trade opium again even though China had already made the opium trade illegal and resulted in China opening more trading ports and giving more freedom to foreigners that visited China. 

Arthur Wellesley was born in 1769 and entered the military at age 18 and quickly rose through the ranks and eventually became a general while fighting Napoleon. He was promote to Field Marshall in 1813 after a victory and after the first war was given the title of Duke of Wellington and also became Ambassador to France. When Napoleon came back to try and recapture his throne Wellington led the British forces and fought along with the Prussians to defeat Napoleon at Waterloo. After that victory he went on to have a distinguished career in politics, including serving twice as Prime Minster. Wellington is revered as one of the finest military commanders in British history.

The assassination of Ernst vom Rath was the most proximate cause of the pogrom of Kristallnacht (also known as The Night of Broken Glass). Kristallnacht took place over two days in April 1938.