Forgotten Alien Emblems
by Jörg Hillebrand and Bernd Schneider
TOS: Errand of Mercy
The first time that Klingons appear in Star Trek is in TOS: "Errand of Mercy", as occupying force on Organia. There is no sign of the famous Klingon trident emblem yet. But when Kor is holding the proclamation imposing an assembly ban on the Organians (conveniently written in English!), we can make out something like a logo on the top of the sheet. At least it would have to be something official and not just an ornament if the proclamation were human-made. The idea that the logo is indeed meant to be the emblem of the Klingon Empire (or that of the Klingon Defense Force) at the time is corroborated by an apparently wooden wall relief that serves as a torch holder in Kor's office. It has the same pattern as the logo on the sheet. Hence, it is evident that the wall ornament must be of Klingon origin and was not simply taken over from the Organians. And since the two logos are the same, they should have a certain significance beyond being mere decoration.
TOS: Elaan of Troyius
The familiar Klingon emblem appears for the first time in "Elaan of Troyius". However, we can still see the old one from "Errand or Mercy" on one occasion in the episode. Kirk is holding up a Klingon silver-golden communicator whose lid is adorned by the emblem. Actually, Kor was using such a communicator already in "Errand of Mercy", we just couldn't recognize the emblem that was probably already there.
The commonly known emblem can be seen in TOS: "Elaan of Troyius" behind the Klingon commander. It also adorns the hull of the D7-class battlecruiser that makes its first appearance in the episode as well, although this detail is not really recognizable in the not yet remastered version of the episode. It is noteworthy that both new emblems in "Elaan of Troyius" are horizontally oriented (meaning that the one on the hull points inward instead of forward), as opposed to the many later variations (including the ones from Star Trek Enterprise) all of which are upright. It may have been decided at the time of "Star Trek: The Motion Picture" to turn the emblem 90° so it would look more impressive. The K't'inga-class cruisers in this movie still have the colorful version of the logo, but now pointing forward.
Actually, in TAS: "The Time Trap", the Klingon emblem can be seen with a still different orientation: upside down! (More precisely, with green and blue switched.) We may surmise that this was accidental.
Finally, in VOY: "Barge of the Dead", we can see an upside-down emblem at the gate of Gre'thor, here with a specific reason as it symbolizes the Klingon hell.
TOS: The Enterprise Incident
In TOS: "Balance of Terror" there was nothing like a Romulan emblem, although the painted bird on the ship's hull, that history buff Lt. Stiles already hinted at, qualifies as a distinctive mark of a similar nature. Anyway, it is obscure but something like a Romulan emblem shows up in TOS: "The Enterprise Incident". It is visible only briefly in a corridor, above a door.
While it may be just a decoration or a pictogram denoting a certain section of the ship, there is one reason why it was likely intended to be the Romulan emblem indeed. It looks remarkably similar to the Klingon emblem that had premiered just a few episodes earlier, in "Elaan of Troyius" (see above). It is even composed of the same colors. So whoever created this supposed Romulan emblem had a good intention to give this race more distinctiveness, but should have come up with something much more original to that end. Yet, perhaps the set designers deliberately made it look like the Klingon trident. The latter can be found on the ship's hull and may have been recognizable in the episode (the Romulans are using Klingon D7 cruisers in this episode). So the Romulan emblem may have been made to look similar. A possible retroactive in-universe explanation is that the logo symbolizes the supposed short-lived alliance of the Romulans with the Klingons in the 2260s. The colors were taken from the Klingon emblem, while the unknown individual Romulan emblem may have contributed the hexagonal shapes.
Interestingly the regular hexagon already appears on a Romulan helmet in TOS: "Balance of Terror", while a variety of elongated coffin-shaped hexagons can be seen on Vulcan in TOS: "Amok Time".
The now familiar double-headed bird-of-prey emblem of the Romulans (apparently a homage to the painting on the ship's hull in "Balance of Terror") is supposedly holding the two planets Romulus and Remus in its claws. It appears as late as in TNG: "The Neutral Zone" on the bridge of the Romulan Warbird (and on the ship's hull too, albeit barely visible).
The same emblem shows up at Paradise City in "Star Trek: The Final Frontier" (set in 2286) beside the Klingon and the Federation emblems. Including the new logo here was the obvious choice, as it had just been established for the Romulans on TNG, albeit 80 years later in the timeline. As we wouldn't have expected otherwise, we can see the "modern" emblem in ENT: "The Aenar" (set as early as 2154) too, actually the more stylized variation created for "Nemesis" on the uniforms that the episode took over from the movie.
Some screen caps from TrekCore. Thanks to Ambassador/Ensign Q and to E.W.G. for suggestions pertaining to the origin of the TOS Romulan emblem and to Nathan for the hint about the Romulan hexagon in "Balance of Terror".