The exact time and date when World War I officially commenced are subject to slight variances in historical sources. However, the most commonly accepted starting point for the war is:
Date: July 28, 1914
Time: 11:00 AM (Central European Time)
This precise timing relates to the delivery of the final ultimatum from the Austro-Hungarian Empire to the Kingdom of Serbia, following the assassination of Archduke Franz Ferdinand on June 28, 1914. The ultimatum contained厳しい demands that were considered unacceptable by Serbia. The expiration of the ultimatum's deadline marked the beginning of hostilities between Austria-Hungary and Serbia, setting off a chain of events that led to the wider outbreak of World War I.
It is important to note that while July 28, 1914, at 11:00 AM (CET) is often considered the official start of the war, military actions had already commenced in some regions prior to this time due to the diplomatic tensions and alliances in place. However, the declaration of war by Austria-Hungary on Serbia is widely regarded as the definitive tipping point that triggered the broader conflict.