The origin of the custom of worshipping the snake Goddess Manasa can be traced to the 'Sarpabali' ceremony of the Grihya Sutras. Sarpabali ceremony was being performed during the rainy season for the purpose of honouring and warding off the snakes. The Manasa cult was widely popular through the eastern parts of ancient India especially during the period of Jainism and Buddhism. Based on the Mahabharat', the snake Goddess Manasa is currently identified with Jaratkaru - sister of Vasuki and wife of Sage Jaratkaru.
In the Brahma Vaivarta Purana, Manasa has been described as the
mind born child of Kasyapa, but the spiritual daughter of Shiva who instructed
her to go to Pushkara and meditate there on Bhagavan Sri Krishna.
The popularity of the cult of Manasa during the 16th century
A.D. is known from the biography
of Sri Chaitanya and the 'Manasa Mangala' by Vijaya Gupta of Phullasri
(Bakhargan).
The snake cult or Nagas is more closely associated to Shiva.
Mahadeva Shiva is worshipped as Nageshwar. So, it is believed that Manasa was the
daughter of Shiva. It is believed that Goddess Manasa once met Shiva and sought
the boon that human beings should worship her. Shiva gave her the boon and
blessed her that a every month of the lunar year a festival will be observed in
her honor.
Goddess Manasa is usually depicted with two hand and she holds
a lotus and drinking pot. A five-hooded snake protect her by forming a canopy.
When the murti has four hands, she
is seated in lalitasana, right leg resting on a lotus flower and left
leg crossed on the pedestal. She holds a Dambaru encrircled with serpent
coil in the right upper hand. The left upper one a trident and left a
small drinking pot.