According to the Koti Rudra Samhita of Shiva Purana, once Ravana, the 10 headed demon king of Lanka, started a severe penance to Lord Shiva. He wished to take Shiva to Lanka. Ravana prayed and meditated on Mount Kailash for years, but his prayers were not answered. Finally, he started chopping his heads to please the Lord. When he finished chopping the 9 heads and was about to chop the 10th, the last head, Lord Shiva was impressed. He appeared and returned back the heads and also cured the damage.

Also, in continuation to the above story, Ravana was granted a boon to take the Atmalingam to Lanka but with a condition that when and if the Lingam touched the ground, it would stay there forever and couldn’t be lifted. The Devas did not want the Atmalingam to be taken to Lanka, hence conspired in such a way that Ravana had to trust a cowherd boy to take care of the Lingam. As the cowherd held on to the Shivalinga, he started feeling it grow heavier by the minute. Soon, it became impossible for the cowherd to carry the heavy shivalinga in his hands and he put it down on the ground and left. This Shivlinga is the Deity of Baidyanath.