Long ago before Lululemon was the norm in class, there was a dude named Paulie Zink who taught Taoist Yoga. He was also a master of martial arts and used his yoga practice as the base/foundation for his training. He would start with supine poses which he held for 5-10 minutes. Two hours later, Paulie would begin the Yang portion of his training. At this point in time, Taoist Yoga is what we know as Yin yoga today. However, not in its entirety. Only the part dealing with Yin principles.
Taoist Yoga | Father of Yin Yoga
Paul Grilley is the most well-known teacher in the Yin style. He met Paulie Zink in 1989 and trained with him for one year.