First Federation/Romulan War

The First Federation/Romulan War was the name of an interstellar conflict between the United Federation of Planets and the Romulan Star Empire fought in the late 24th century.

The war began in 2377, when Romulan forces crossed the Neutral Zone, attacking several key systems along the border.
The Romulans' hope was to take advantage of the Federation's weakness following the Federation/Dominion War.
Initially, the Romulans made great gains in the first year and a half, catching the unprepared Star Fleet by surprise.

Eventually, the Federation economy responded to the Romulan threat, with defenses roaring to life.
Starship production increased dramatically, and reached levels not seen before, not even during the Federation/Dominion War.
By mid-2378, Star Fleet forces stopped the Romulan advance, and slowly began pushing them back into their own territory.

The war officially ended in 2379 with the signing of the Sendarian Accords, which restored the original neutral zone and returned all territories to their original owners.
The accords also re-established the conditions of the Treaty of Algeron, including the ban on cloaking devices in the Federation.