Navratri is one of the most important Hindu festivals and is celebrated in various parts of India with reverence and faith. The history and origin of Navratri is different in diverse parts of India.
In North India, people believe that there was a demon named Mahishasura who worshiped lord Shiva and obtained the power of eternity. But, he used the power in a wrong way. He began killing people and built up his army to take all the three loks by himself. By watching this, all the Devtas went to Lord Shiva and asked him to get rid of this demon. To kill this demon and protect the world, the three supreme powers Brahma, Vishnu and Mahesh combined their powers and created a divine female power known as goddess Durga. Goddess Durga was so beautiful that mahishasura got mesmerised by her beauty.
He was so convinced that he approached her with the intentions of marrying her. The goddess agreed to marry him but put a condition. She asked him to win over her in a battle. The proud demon agreed onto that and the battle began. The battle continued for nine nights and at the end of ninth night, she killed the demon Mahishasura. For this reason, the nine days are known as navratri. The tenth day is known as Vijayadashmi as it is celebrated for the victory of good over evil.
Raja Daksha Yagya:
Easterners believe that there was a king named Daksha (king of Himalayas). He had a beautiful and victorious daughter called Uma. She always wanted to marry Lord Shiva. In order to get him, she began worshipping him and with her hard austerity and finally she managed to please him. When lord Shiva came to marry him, his terrifying appearance displeased Daksh and he broke all the relations with her daughter.
One day, Daksha organised a yagya and invited all his known belongings and friends but did not invite lord Shiva. This made Uma angry. She couldn’t stand the insult her father did to her husband and she decided to end her life by jumping into the agnikund of that yagya. However, she took birth again and gave birth to Ganesha and Kartik.
As per another mythology, Lord Rama also worshiped Goddess Durga in her nine forms for nine days in order to get strength to kill Ravana. Those nine nights are known as Navratri.