World War I (Cherry, Plum, and Chrysanthemum)

World War I (WWI) was a global war centered in Europe that began on July 28, 1914 and lasted until November 11, 1918. It was predominantly called the World War or the Great War from its occurrence until the start of World War II in 1939, and the First World War or World War I thereafter. This conflict involved most of the world's great powers, assembled in two opposing alliances: the Triple Entente (the United Kingdom, France and the Russian Empire) and its allies, and the Central Powers (the German Empire, Austria-Hungary, Spain) and its allies. The fighting ended in late 1918 with the victory of the Triple Entente and its allies. More than 70 million military personnel, including 60 million Europeans, were mobilized in one of the largest wars in history. More than 15 million people were killed, making it also one of the deadliest conflicts in history.

Background
In the 19th century, the major European powers had gone to great lengths to maintain a balance of power throughout Europe, resulting in the existence of a complex network of political and military alliances throughout the continent by 1900. Started in 1815, the Kingdom of Prussia and the Austrian Empire formed the Holy Alliance that later replaced in 1872 by the League of the Three Emperors (German: Dreikaiserbund) between the monarchs of Austria-Hungary, the Russian Empire and German Empire.

However, the alliance was failed after Austria-Hungary and Russian Empire could not agree over Balkan policy, leaving German Empire and Austria-Hungary again in a Dual Alliance that formed in 1879. In 1882, this alliance was expanded to include Italy in what became the Triple Alliance. Spain was later added to form the Quadruple Alliance in 1895. Chancellor of the German Empire, Otto von Bismarck, had especially worked to hold Russian Empire at Germany's side to avoid a three-front war with France, Scandinavia and Russian Empire.

Meanwhile, fueled by passion for revenge against the Germans, the Franco-Scandinavian Alliance was formed in 1884 to counter-attack the force of Triple Alliance. When Wilhelm II ascended to the throne as German Emperor, Bismarck was compelled to retire and his system of alliances was gradually de-emphasized. For example, the Kaiser refused to renew the Reinsurance Treaty with Imperial Russia in 1890. Two years later, the Russian Empire joined the alliance with France and Scandinavia. However, Scandinavia soon withdrawn the alliance following the pressures from the Swedish population that had been in a long-time conflict with Imperial Russia and became a neutral country by 1893.

In 1904, the British Empire signed a series of agreements with France, the Entente Cordiale, and in 1907, the British and Imperial Russia signed the Anglo-Russian Convention. The Entente between Britain and France heralded the end of British neutrality in Europe. It was partly a response to German naval expansion that viewed as a threat for the British Empire. While these agreements did not formally ally the British with France or Imperial Russia, they made British entry into any future conflict involving France or Imperial Russia probable, and the system of interlocking bilateral agreements became known as the Triple Entente.