The Tomed Incident was a horrific act of terrorism in February 2311 that cost thousands of Federation lives. History records that Romulan Admiral Aventeer Vokar, an extremist in the Romulan Imperial Fleet, ordered his ship, the Tomed, abandoned by all but six of the crew. From there, Vokar and his cohorts set course for the Foxtrot Sector in Federation space.
Upon reaching their destination, the ship impacted with an asteroid base, and its quantum singularity drive caused a massive explosion due to the fact that singularity containment was lost whilst the warp field was still active, disrupting space-time throughout the sector and wiping out dozens of asteroid bases and at least one starship, the USS Agamemnon. Thousands of lives were lost, with only the USS Enterprise-B escaping destruction.
Vokar apparently commited this heinous act in the hopes of prompting a war between the Federation and the Romulan Star Empire due to his long-standing Romulan chauvinism and imperialistic stances. The Tomed Incident nearly accomplished Vokar's goal before the Klingon Empire, previously neutral, sided with Federation forces, thus prompting the Imperial Fleet to retreat from the border.
Two months after the Tomed Incident, the Romulan Star Empire forced the Federation to sign a revised Treaty of Algeron that banned the development of cloaking technology within the UFP in return for the Star Empire's agreement to withdraw behind its borders and to recall all of its diplomatic missions and citizens, effectively isolating them on the astropolitical scene.
Models by Rick Knox