Romulan-Vulcan War
The Romulan-Vulcan War was a conflict between the Romulans and Vulcans which started sometime before the 21st century and lasted a hundred years. 

The incident which sparked the war was inadvertently caused by Quinn, who was trying to commit suicide. His events created a misunderstanding between the Romulans and Vulcans.

In 2372, Q referenced this event to Kathryn Janeway, describing it as a "self destructive stunt" that demonstrated Quinn's harm to others. ()

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Apocrypha
In The Way of D'era, the Romulan-Vulcan War took place from the Earth year 1270 to 1370 after the wormhole which had brought them to Romulus reappeared and then collapsed after a hundred years, thereby putting an end to the conflict. The defeat of the Star Empire saw a weakening of the position of the Emperor of the Romulan Star Empire, which in turn made the position of Praetor rise in power.
de:Vulkanisch-Romulanischer Krieg

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Conflicts