Star Trek: 10 Things You Need To Know About The Lost Era

Serpents Among the Ruins tells us the intricate story of the Tomed Incident. The Tomed was the Romulan flagship under the command of the belligerent Admiral Aventeer Vokar. Captain Harriman, along with two other SI operatives, managed to hijack the Tomed to use it as a kind of false false flag. They launched the ship at the 'Foxtrot Sector' asteroid base, destroying it and various other bases in the resulting explosion, 'killing thousands,' or so it would seem.

All of the 'Tomed Incident' deaths had, in reality, been manufactured in advance. Harriman tried to get all of the Romulan crew off the ship first, but a few stubbornly remained on board, including Vokar. The Klingons then sided with the Federation, thus forcing the Romulans to stand down and to talk peace at Algeron.

From canon, we only know that the Treaty of Algeron was signed into agreement in 2311. It redefined the Romulan Neutral Zone and forbade the Federation from using and developing cloaking devices. In Serpents Among the Ruins, Harriman concocted a "failed trial" of a "hyperwarp drive" on the new starship Universe to lure the Romulans into thinking that "the Federation was seeking a first-strike capability through the development of a vastly improved engine system." In reality, the 'hyperwarp drive' was just a combination of cloaking tech. and the already failed transwarp drive. Plus, as the novel states, Starfleet had always had an "aversion to the use of cloaking devices."

During the Algeron negotiations, Starfleet and the Federation needed a bargaining chip to get something they wanted in return — "the freedom of the Koltaari," a pre-warp people invaded and enslaved by the Romulans. To do so, they handed over the specs to the hyperwarp non-starter to the Romulans (and the Klingons) and then feigned any imposition of having to give up cloaking technology.

Admiral Pressman really was barking up the wrong tree.