If you want to talk about the politics of the Star Trek galaxy, you have to talk about the Romulans. And in order to really understand what's going on in Star Trek: Picard, it's a good time to brush up on your knowledge of the pointy-eared aliens who are not the friendly Vulcans.

Each of the trailers for Star Trek: Picard feature several Romulans, including the sword-wielding Elnor (Evan Evagora), a young member of Picard's new crew, and Narek (Harry Treadway), a bad guy who is clearly up to no good. Additionally, at several points in the trailer, we also see a retro Romulan Bird-of-Prey starship, straight out of the style from the original Star Trek. Notably, Picard also takes place in the aftermath of the future-events of the 2009 Star Trek reboot, in which we learned that the Romulan home planet — Romulus — was destroyed by a giant supernova. So, in theory, the Romulans in the Picard-era will be without a home planet.

Bottom line: The Romulans will be a big deal in the new series. Right now, a three-part IDW comic book series called Picard: Countdown is outlining how Picard tried to help evacuate several Romulan planets while he was still an Admiral in Starfleet. But, the overall history of the Romulans in Star Trek is worth taking a look at.

Here are nine essential Romulan-centric episodes and films to rewatch before Picard debuts.

**Spoiler Warning: There are spoilers ahead for The Next Generation, Deep Space Nine, and the movies. No spoilers ahead for Picard.**

Note: For episode numbers of individual Star Trek series, I'm using the Netflix order, which, in some cases, will differ from the way the episodes aired. However, this order is easiest if you want to stream these right now.