Haṭha Yoga and the Haṭhapradīpikā

Study of an earlier eleventh-century source text has shown that some of the tradition's core physical techniques actually entered from an earlier Buddhist text, reversing the standard account of where the practice originated. The pre-modern text itself describes only about fifteen postures — a small fraction of the sequences taught in a modern class.

Svātmārāma, Haṭhapradīpikā (c. 1450); the Amṛtasiddhi (c. 11th c.), showing Buddhist origins for core techniques