Caligaris Epsilon Six was a holiday planet active in the 77th and 78th centuries. It was designed and constructed to resemble a fantastic medieval European version of Earth, complete with genetically engineered elves, cyborg dragons and robotic fairies.
It was placed under planetwide quarantine for recombinant yersinia pestis in 7711; the quarantine was lifted some hundred fifty years later, with the assistance of the Eleventh Doctor and Amy Pond. (IDW: A Fairytale Life)