When some members of Zarabeth's family crossed Zor-Khan, retribution was paid by Zarabeth being exiled deep in the ice age that occurred 5,000 years in her world's past history. Zarabeth was forced to time travel, being processed by the atavachron technology to be suited only to life in the ancient past, meaning it would be impossible for others to retrieve her by means of the atavachron, essentially trapping her in that time period.
In the 2260s decade, information about Zor-Khan was stored on file at the library of Mr. Atoz. When a landing party from the starship USS Enterprise visited the world, Spock was testing the interface of the verism tape terminals in the Atoz library, briefly playing a recording mentioning Zor-Khan. (TOS episode & Star Trek 4 novelization: All Our Yesterdays; TOS - The Yesterday Saga novel: Yesterday's Son)
- It was not specified at what point in history Zor-Khan ruled on Sarpeidon and banished Zarabeth, but it would have had to taken place at a point in Sarpeidon history after the invention of the atavachron technology.