In 2366, the Pi was carrying out a covert mission when it crash landed on the planet Galorndon Core, inside Federation space. The Pi was destroyed with an ultritium explosive after the crash to prevent its capture by Starfleet. The USS Enterprise-D followed their distress signal and found the wreckage, determining it not to be salvageable. Two Romulan crew members were eventually retrieved. (TNG: "The Enemy")
Background information Edit
The mission of the Pi was not revealed in the episode.
Pi was a Greek letter, although it was unknown if there was any relation. In this usage, though, the "relationship" is most likely simply homophonic.
The Starships RPG sourcebook gives its registry as IRC-13301.
The name Pi was later used for a Romulan Griffin-class ship instead of the scout ship type in the game Star Trek: Armada.