Yoga's transmission has never run through a single channel. Vedic and Upanishadic material passed through Brahmanical teacher-student lineages; the Yoga Sutras generated a long Sanskrit commentarial tradition; and hatha yoga circulated chiefly through the Nath order of ascetics and later through Hindu and, notably, Sufi-influenced manuscript traditions in North India. Guru-to-disciple transmission has been the normal mode throughout, though the content transmitted changed considerably across periods. The decisive break came in the colonial and early independence periods. Reformers such as Vivekananda, addressing Western and Indian elite audiences from the 1890s, presented yoga chiefly as philosophy and meditation and downplayed the ascetic, ash-smeared hatha yogi as an embarrassment to a modernizing India.
A different lineage, running through Mysore court gymnastics, the Indian nationalist physical culture movement and direct contact with European systems such as Scandinavian gymnastics and British Army drill, produced the asana-centered practice that Krishnamacharya taught from the 1930s and that his students, including K. Pattabhi Jois and B. K. S. Iyengar, carried into the postwar global yoga industry.
The scholar Mark Singleton has documented this synthesis closely, showing that the standing sequences and vinyasa flow characteristic of much modern yoga have little precedent in the Indian textual tradition before the twentieth century. This does not make modern yoga inauthentic so much as it makes it a distinct, dated historical development, and the relationship between it and the older textual traditions is a live scholarly question rather than a settled lineage.