Fourth Anglo-Mysore War happened in 1798.
Fourth Macedonian War happened in -150.
Fourth Anglo-Dutch War happened in 1780.
War of the Fourth Coalition happened in 1806.
The duration of The Fourth War is 1.52 hours.
The Fourth World War was created in 2003.
The Fourth War was created on 1990-03-23.
The fourth Arab-Israeli War began in October 1973.
There hasn't been a confirmed source about a fourth, but it MIGHT happen. The titles (that have not been confirmed) are either Clash or War.
Fourth Battle of the Isonzo happened on 1915-12-02.
Fourth Battle of Brega happened on 2011-07-21.
Fourth Battle of Topolobampo happened on 1914-06-16.
Fourth Amendment of the Constitution of Ireland happened in 1972.