Origin of Durga - The Mythology

Devi is the great goddess of the Hindus,the consort of Shiva and she is worshiped in various forms corresponding to her two aspects: benevolence and fierceness. She is Uma, "light"; Gauri, "yellow or brilliant"; Parvati, "the mountaineer"; and Jagatmata, "the-mother-of-the-world" in her milder guise. The terrible emanations are Durga "the inaccessible"; Kali, "the black"; Chandi, "the fierce"; and Bhairavi, "the terrible."
Descent of the Goddess
Durga, a beautiful warrior seated upon a tiger, was the first appearance of the great goddess. The circumstance of her miraculous arrival was the tyranny of the monster-demon Mahishasur, who through terrific austerities had acquired invincible strength. The gods were afraid of this water-buffalo bull because neither Vishnu nor Shiva could prevail against him. It seemed that the joint energy of Shakti was only capable of vanquishing Mahisha, and so it was the eighteen-armed Durga who went out to do battle. 

Battlefield 
She went to battle on her ferocious mount lion, armed with the weapons given to her by the other Gods. Durga is one of the angry and aggressive aspects of the goddess Shakti, whose role in Hindu mythology was to fight and conquer demons and also personify the Sakti or female aspect of any male deity. In the battle, she fought and killed the evil Mahishasura and restored heaven to the Gods. Since then the goddess is invoked for protection from the powers of evil. Durga Puja is observed in her honor, to celebrate her victory over evil. 

Revered Mother
She has been worshiped from about 400 AD, but probably earlier, to the present. Her literary references are chiefly the Ramayana and Mahabharata, epic and Puranic texts, and she is mentioned by name in Vedic literature. In general, Durga is regarded in northern India as the gentle bride epitomizing family unity while in southern India she is revered more in her warrior aspect.

Navratri

Navratri, the festival of nights, lasts for 9 days with three days each devoted to worship of Ma Durga, the Goddess of Valor, Ma Lakshmi, the Goddess of Wealth and Ma Saraswati, the Goddess of Knowledge. During the nine days of Navratari, feasting and fasting take precedence over all normal daily activities amongst the Hindus. Evenings give rise to the religious dances in order to worhip Goddess Durga Maa.
1st - 3rd day of Navratri 
On the first day of the Navaratras, a small bed of mud is prepared in the puja room of the house and barley seeds are sown on it. On the tenth day, the shoots are about 3 - 5 inches in length. After the puja, these seedlings are pulled out and given to devotees as a blessing from god. These initial days are dedicated to Durga Maa, the Goddess of power and energy. Her various manifestations, Kumari, Parvati and Kali are all worshipped during these days. They represent the three different classes of womanhood that include the child, the young girl and the mature woman. 

4th - 6th day of Navratri 
During these days, Lakshmi Maa, the Goddess of peace and prosperity is worshipped. On the fifth day which is known as Lalita Panchami, it is traditional, to gather and display all literature available in the house, light a lamp or 'diya' to invoke Saraswati Maa, the Goddess of knowledge and art. 

7th - 8th day of Navratri 
These final days belong to Saraswati Maa who is worshipped to acquire the spiritual knowledge. This in turn will free us from all earthly bondage. But on the 8th day of this colourful festival, yagna (holy fire) is performed. Ghee (clarified butter), kheer (rice pudding) and sesame seeds form the holy offering to Goddess Durga Maa. 

Mahanavami 
The festival of Navratri culminates in Mahanavami. On this day Kanya Puja is performed. Nine young girls representing the nine forms of Goddess Durga are worshiped. Their feet are washed as a mark of respect for the Goddess and then they are offered new clothes as gifts by the worshiper.