Warning: This Article Contains SPOILERS for Star Trek: Discovery Season 5, Episode 5 - "Mirrors"

Summary

• Star Trek: Discovery season 5, episode 5, "Mirrors", reveals new details about the Mirror Universe's history on the ISS Enterprise.
• The dedication plaque on the starship sheds light on events in the late-23rd century after "Mirror, Mirror" from TOS season 2.
• Burnham and Booker found the ISS Enterprise in interdimensional space and brought it into the 32nd century Prime Universe.

Star Trek: Discovery season 5, episode 5, "Mirrors", shockingly brought the ISS Enterprise into the 32nd century, and the starship's dedication plaque reveals new details about the Mirror Universe's history. Written by Johanna Lee and Carlos Cisco and directed by Jen McGowan, "Mirrors" brought Captain Michael Burnham (Sonequa Martin-Green) and Cleveland Booker (David Ajala) into interdimensional space in pursuit of the next clue to the ancient treasure of the Progenitors, which was hidden aboard the 23rd century ISS Enterprise from the Mirror Universe.

On his X account, Jörg Hillebrand (@gaghyogi49), who was a researcher for Star Trek: Picard season 3 renowned for his attention to detail, posted a clear translation of the ISS Enterprise's dedication plaque from Star Trek: Discovery season 5, episode 5. The illuminated text reveals what happened in the late-23rd century Mirror Universe after the events of Star Trek: The Original Series season 2's "Mirror, Mirror." Read the post below:

Here is the image in the X post:

A Timeline of Star Trek's Mirror Universe

From the Terran Empire to the Temporal Wars

The Mirror Universe was introduced in Star Trek: The Original Series season 2's "Mirror, Mirror" and its canonical history can be tracked through Star Trek: Deep Space Nine, Star Trek: Enterprise, and Star Trek: Discovery. The earliest chronological glimpse of the Mirror Universe is on April 5, 2063, when Zephram Cochrane (James Cromwell) murdered a Vulcan after making First Contact in Enterprise's "In A Mirror, Darkly". In the 22nd century of Star Trek: Enterprise's Mirror Universe, Commander Jonathan Archer (Scott Bakula) captured the USS Defiant from the 23rd century, but he was betrayed by Hoshi Sato (Linda Park), who declared herself Empress of the Terran Empire.

In the 23rd century of Star Trek: Discovery, the Mirror Universe was ruled by Emperor Philippa Georgiou (Michelle Yeoh). Georgiou jumped to Star Trek's Prime Universe aboard the USS Discovery after defeating a coup by Gabriel Lorca (Jason Issacs). The Terran Empire continued unabated, but after Captain James T. Kirk (William Shatner) briefly switched places with his Mirror Universe counterpart, he convinced the Mirror Spock (Leonard Nimoy) to institute reforms to save the Terran Empire from its inevitable collapse.

Refugees fled the Mirror Universe aboard the stolen ISS Enterprise.

Star Trek: Discovery season 5 episode 5 reveals that High Chancellor Spock did change the Terran Empire, but he was assassinated for weakness. Refugees fled the Mirror Universe aboard the stolen ISS Enterprise, thanks to the Mirror Saru (Doug Jones), a rebel leader. The ISS Enterprise's personnel did make it to the Prime Universe. However, in the Mirror Universe, the Terran Empire was conquered by the Klingon/Cardassian Alliance, as detailed in Star Trek: Deep Space Nine. By Star Trek: Discovery's 32nd century, the Mirror and Prime Universe timelines have split further apart thanks to the Temporal Wars, making crossing over impossible.

Source: Twitter/X

New episodes of Star Trek: Discovery season 5 stream Thursdays on Paramount+