Dussehra, as other important festivals of the Hindus, has several stories related to it. All these stories have a common theme which clearly states that Dussehra marks the victory of the good over the evil. It has stories related to it from the Ramayana and Mahabharata.
The Origin and Legend of Dussehra
The festival of Dussehra draws its origination from the great Hindu epic Ramayana which says that the eighth incarnation of Lord Vishnu, Lord Rama killed the ten headed devil Ravana in the Sat-yuga, since Ravana had abducted Lord Rama's wife Sita.
Lord Rama was accompanied by his brother Lakshman and follower Hanuman with an army of monkeys who went all the way to Lanka (Ravana's kingdom) to fight Ravana and bring back Sita. On their way, Rama prayed to Durga, to seek the blessings of the goddess of courage and power.
Lord Rama finally killed Ravana and won over the evil. To commemorate this day, Vijayadashmi or Dussehra is celebrated.
The Story of Dussehra
There are a number of stories related to the reason of celebration of Dussehra. Following are some of the most famous and prevalent stories:
Assassination of Mahishasur
According to the Hindu stories, the demon Mahishasur had been troubling all the Gods of the Swarg Lok and the living beings since he had acquired undefeatable power. Even the mighty gods, Lord Vishnu, Lord Shiva and Lord Brahma couldn't defeat him themselves. So they decided to do something in order to free the living beings and restore the Swarg Lok.
So they gave rise to Goddess Durgs who is despotism of Ma Shakti and gave her the god-like weapons. As promised, she killed Mahishasur and so Vijayadashmi is celebrated as her victory over him.
Worship of the Shami tree
Another story originates from the epic Mahabharata. As per the story the Pandavas had to spend 12 years of exile and one year of disguise since they were banished and defeated by the Kauravas in the game of gambling (Chaucer). So they planned to spend the last year of there exile in disguise. Since they did not want any other to know about there identities they hid their divine and powerful weapons under the Shami tree.
At the end of the one year of disguise they came back to find their weapons and worshipped Goddess Durga, the deity. They went straightaway to the war against Kauravas after fetching their weapons and later emerged victorious.
The event took place in Dasmi and since good had won over the evil, that day was called 'Vijayadashmi' and is celebrated till date.