Priscillian, a Spaniard of noble birth, who introduced a Gnostic and Manichæan heresy into Spain, and founded a sect called after him, and was put to death by the Emperor Maximius in 385; his followers were an idly speculative sect, who practised a rigidly ascetic style of life, and after being much calumniated did not survive him over 60 years.
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Priscian * Prismatic colours