Welcome to Trekspertise, a series where we break down the technology, history, details, and decisions that make the Star Trek universe so complex — and so fun. Cloaking devices were first introduced on "Star Trek" in the original series episode "Balance of Terror," showing that Romulan vessels could somehow make their ships appear invisible. Cloaking devices have been a regular feature on "Star Trek," then, since the very beginning. Said treaty was signed in the year 2311, about 20 years after the events of "Star Trek VI: The Undiscovered Country," but 50 years before the events of "Star Trek: The Next Generation." Cloaking devices are used by villains, not heroes.