History of Yin
Regardless of the historicity or authenticity of Taoist Yoga, it was in the Taoist Yoga classes that Paul Grilley attended where Paulie Zink offered asana/posture practice that included both Yin postures and Yang movements. While Paulie's Taoist Yoga was interesting, what Paul really resonated with was the long held postures. He got the idea that an entire yoga class could be Yin in nature without any Yang postures at all: an entire Yin Yoga practice was possible. He started offering this "All-Yin" practice to his own Hatha Yoga students, and they too started to resonate with the practice.
Sarah Powers loved the Yin practice she learned from Paul Grilley. She became convinced that Yin Yoga had to be an essential part of her own practice. Now in 2017 there seems to be a YIN wave breaking on the many shores around the globe.