Turn the corner of almost any Shiva temple in the south and on the wall that faces south you find him: a young Shiva under a banyan, seated on a deer-skin throne, one foot pressed on the dwarf of forgetting, a hand raised in the sign of knowledge. Old sages sit below him. Nothing is being said. That is the point: the teaching of Dakshinamurthy, the south-facing form, is that the highest truth is given in silence, and the pupils are older than the master because wisdom is not a matter of years. A hymn ascribed to Adi Shankara spells out what the silence means: the self within and the one reality are not two. Alangudi and Thiruvanaikaval are among the shrines where the form is honoured above all others. The tradition also names Shiva Adiyogi, the first yogi and patron of yoga, music and the arts.
The Nath yogis call the same first teacher Adinath, the original lord, and tell how his teaching reached men. Shiva was explaining the secret doctrine to Parvati on the shore; a fish lay listening in the water. The fish was Matsyendranath, who carried what he heard into the world and passed it to Gorakhnath, from whom the Nath order descends.
What is different here:
The teacher is named Adinath and the first pupil is an eavesdropper, not the sages; a lineage charter rather than a temple icon.
A contemporary yogic account holds that on the full moon of Ashadha, Guru Purnima, Shiva turned from stillness to teaching and began passing yoga to the seven sages, becoming the first guru. The older meanings of the day are Vyasa's birthday and, for Buddhists, the first sermon at Sarnath.
What is different here:
Adds a calendar date and the seven sages; rests on a modern foundation's telling, with no scripture cited.