Praetorian was a planet.

In 2261, Nurse Christine Chapel and Doctor Roger Korby discovered memory stones on Praetorian that used the same alphabet as ancient texts on Vadia IX and a signet ring from Polaris XII, indicating that all three worlds were once occupied by the same advanced spacefaring civilization.

Later that year, Chapel recalled that some of the artifacts on Praetorian were set into pedestals like those found inside a structure on Vadia IX, suggesting a means to operate the technology. (SNW: "Through the Lens of Time")