10 Most Mysterious Ancient Alien Civilisations In Star Trek

As of the mid-23rd century, the oldest living space faring species known to the Federation were the Vedala. These feline humanoids (similar in appearance to Caitians or Kzinti) were once militaristic conquerors before uniting in the name of peace under a religious figure known as Alar.

The Vedala had very advanced technology for the time period, including the ability to manipulate time. In the episode The Jihad, they enlisted the help of Kirk and Spock to recover the stolen artefact The Soul Of Alar, which contained the consciousness of their religious leader. 

The Vedala feared that a holy war would ignite if it was discovered the artefact was stolen, so when the mission was completed they wiped the team's memories and somehow made it appear that only minutes had passed, despite the mission actually lasting much longer. This could mean they sped up time itself or transported the team back in time after wiping their memories of the mission.