What period marks the commencement and conclusion of World War I?

The period marking the commencement and conclusion of World War I is from 1914 to 1918. This conflict began on July 28, 1914, when Austria-Hungary declared war on Serbia, following the assassination of Archduke Franz Ferdinand. The war involved many of the world's great powers and was characterized by trench warfare and significant battles, including those at the Somme and Verdun. The fighting ended with the signing of the Armistice on November 11, 1918, which effectively marked the conclusion of hostilities, although the formal peace treaty, the Treaty of Versailles, was signed later in 1919. Thus, the dates 1914 to 1918 are pivotal for understanding the timeline and impact of World War I on international relations and society during that era.