Romulan peace envoy
In the late 2360s, the T'Pau and two other unnamed Vulcan starships were stolen from various Federation facilities by Romulan operatives. These vessels were to be used as a "peace" envoy, which were actually used as troop transports, sent to Vulcan in 2368.
Following Starfleet's discovery of the Romulans true intentions, the invasion of Vulcan, the Romulan force retreated toward the Neutral Zone. Upon an attempted interception by the USS Enterprise-D, a Romulan Warbird destroyed the three Vulcan transports and all the troops on board. (TNG: "Unification I", "Unification II")