History Timeline By gracy_ Jun 28, 1914 Assassination of Archduke Franz Ferdinand https://www.history.com/news/did-franz-ferdinands-assassination-cause-world-war-i Jul 28, 1914 War with Serbia https://www.history.com/this-day-in-history/austria-hungary-declares-war-on-serbia#:~:text=On%20July%2028%2C%201914%2C%20one,beginning%20the%20First%20World%20War. Aug 29, 1914 World War https://www.britannica.com/event/World-War-I May 7, 1915 Sinking of the RMS Lusitania https://www.history.com/news/how-the-sinking-of-lusitania-changed-wwi May 10, 1916 Submarine Warfare is Suspended https://www.history.com/this-day-in-history/germany-resumes-unrestricted-submarine-warfare