Phrynian

The Phrynians were the humanoid inhabitants of Phryne. They served as the archivists for the histories, treasures and artifacts of a hundred planets. To protect this knowledge, they hid their solar system (but not their world's own moon) behind an invisibility shield. When the Daleks discovered the moon, they eventually figured out how to pierce the shield and invaded the planet. When the Phrynians' defences proved little match for the Daleks, they fled to the mountains to take refuge, planning to rebuild their weapons and fight again another day. (TV21: The Archives of Phryne)