Charak puja and Gajan is associated with Shiva a deity male post Vedic deity direct heir of the pre- air, later echoed in the Vedas, as indicated by the names of Pashupati and Rudra. Foundation, starting from Gupta period of seven mystical Shiva is dedicated to him now, in the modern age, one of the major cults of Hinduism.
Reconstructing the origin of the worship of this important deity of India, ancient and modern is a daunting task, which has not been fully scholars agree that if they are busy. The hypothesis formulated by the archaeologist John Hubert Marshall, according to which the seals depicting the deity of a prototype Pashupati the Lord of Animals of the Veda found in the Indus Valley could be directly connected to the next deity Shiva, however, is now generally accepted.
The Indus Valley Civilization was a thriving civilization in the Indian subcontinent between Beijing and the XX century BC, who intervened when the ancient civilization was already in decline for several centuries.
The seals depicting this god Pasupati represent the god in anthropomorphic form, with the erect penis, in a posture yogic and the face bovine or three sides of a hairstyle often provided in the form of horns. In one of the seals that figure, placed on a platform, is surrounded by a buffalo, a rhino, an elephant and a tiger, under the platform there are two goats or possibly deer, while the top seven signs are visible, probably a still undeciphered writing.
If this proves founded criticism would drop the connection between the pre-Aryan and Shiva Pasupati, or its precursor Vedic Rudra, as the animal connected to the latter two gods is certainly the bull. Kosambi colleague but also with this proto-Shiva Pasupati, but through an Asura, the demon buffalo Mahisasura, which, however, noted scholar David N. Lorenzen, we have cognizance of a presence next fifteen hundred years.
The same David Lorenzen, if you remember that the thesis George Marshall are generally accepted by scholars, refers to additional discoveries about Indus Valley Civilization irrefutable evidence of a direct link between the proto-Pashupati seal of the Indus, Rudra Vedic and, finally, the post-Vedic Śiva.