Cloaked Romulan warships of the 2150s, first met by Enterprise in 2152 after it strayed into a Romulan minefield.
Earth first met the warships of the Romulan Star Empire in 2152. These cloaked vessels guarded Romulan territory, which was also protected by fields of cloaked mines.
In Minefield, Enterprise strayed into a Romulan minefield; one mine struck the ship and another latched onto the hull, pinning Malcolm Reed beside it as he tried to disarm it. Two Romulan ships decloaked and ordered Enterprise to leave. Archer cut away the hull plating holding the mine and freed Reed, and the ship escaped as the mine exploded.