There are several beliefs associated with Durga Puja and one such belief behind the Bengalis’ celebration of Durga Puja is as follows.
Sati & Lord Shiva Marriage Story:
Daksha Prajaapati, a descendant of Brahma, had a beautiful daughter named Sati. Sati married Lord Shiva without the consent of her father. When Daksha conducted a sacrifice it was attended by participants from all over the universe, including all gods and goddesses, except Shiva, because Shiva was not invited for the sacrifice. Sati attended the sacrifice against Shiva’s desire, but she was very badly insulted by her father. Unable to tolerate this, she sacrificed herself in the fire.
Hearing the sad news, Shiva became furious and he demolished the sacrifice and cut off Daksha’s head. Upon the request and prayers of other gods he replaced the head with that of a goat. Filled with a heart full of sorrow, he picked the remains of his wife’s body and did the terrific dance of destruction and the whole universe trembled. All gods prayed and interfered to stop the cosmic dance of Shiva. Using his disc, Vishnu cut the remains of Sati and the parts of her body scattered at different spots of the country. These places are believed to be the present sites known as Shakthi Peethas.
At last, Shiva cooled down and he stopped the dance when the last piece of the Sati’s body part fell down from his shoulder. Lord Vishnu gave new life to Sati with the name Uma. It is believed that Uma, her children Ganesh and Karthik, alongwith her friends Jaya and Bijaya used to visit her parent’s home during the autumn or Sharat season every year when Bengali’s celebrate Durga Puja.