The Masters were an ancient race that inhabited the Rigel system over a million years ago, and were responsible for modifying its star and planets and creating some of the species that inhabit it. They were the fourth civilized race to evolve on Rigel IV, around 99,998,000 BCE (reference stardate −1,000,000/00), while Rigel was still young. With an early understanding of science and philosophy giving them great power, they developed a massive empire over the Orion Arm, which lasted for over a million years. The Masters destroyed lesser, rival civilizations, and performed many experiments upon other life forms and cultures.