Further to the idea about the mythical "three patanjalis", please, please everyone note that there is no medical Patanjali. There does not exist a major author of a medical treatise in Sanskrit who is called Patanjali.
If you wish to pursue the details, the name has been investigated in detail by Meulenbeld in his History of Indian Medical Literature (especially IA: 141-44, 196). As a person's name in medical literature, "Patanjali" lives a ghostly life as a name cited by others, as a legendary authority, as a person after whom recipes are named, etc. etc. Most of these occurrences are from the second millennium of our era, and after the first "three Patanjalis" assertion by Bhoja Deva. But even with these "Patanjali" whispers, it remains the fact that there does not exist an identifiable medical treatise by an author called Patanjali.
I'm sorry to shout. But it baffles me to see the continuing repetition of the idea that there was a medical Patanjali when there simply wasn't one. Never has been. Fake News!
Best,
Dominik