Avatars of Vishnu are collectively known as "Dasavatara" in the basic Hindu Trinity of Vishnu, Brahma and Shiva. The Puranas speak of the 10 avatars of Vishnu. These Avatars play a major role in shaping human evolution through centuries. The Bhagavad Gita mentions their purpose to demonstrate that divinity re-establishes Dharma or righteousness and destroys injustice from time to time, by appearing on earth in various incarnations. This list is included in the Garuda Purana and denotes those avatars most prominent in terms of their influence on human society.

The first four avatars of Lord Vishnu are said to have appeared in the Krita Yuga. The next three avatars appeared in the Treta Yuga, the 8th incarnation in the Dwapara Yuga and the 9th in the Kali Yuga. The 10th is predicted to appear at the end of the Kali Yuga in some 427,000 years time.

Dasavatara of Lord Vishnu
The Dasavatara of Lord Vishnu is discussed below:

1. Matsya: This was the form of the fish, taken up by Vishnu during a deluge that submerged the earth. Matsya is generally represented as a four-armed figure with the upper torso of a man and the lower of a fish. According to a legend, Vishnu commanded a rishi to gather samples of all species and wait in a boat. The gigantic golden fish then dragged the boat through the deluge and then enabled Brahma to start the act of creation all over again.

2. Kurma: In this incarnation, Lord Vishnu took the form of a tortoise. According to this legend, the Gods and Demons united in their efforts to churn the celestial ocean of milk, in the quest of Amrit. This mammoth task was carried out with the Mandara Mount as the churning stick and the mythological snake Vasuki as the rope. Thus, Lord Vishnu incarnated himself as the Kurma in order to support the mount Mandara, which started sinking during the churning of the ocean.

3. Varaha: Varaha is the third avatar of Vishnu, who appeared in order to defeat the demon Hiranyaksha. Varaha is depicted as having a boar"s head on a man"s body. Since, the demon had taken the earth and carried it to the bottom of the cosmic ocean, the Lord killed the demon and lifted the earth out of the flood waters in which it had been submerged. He lifted the Bhumi Devi (Earth), between his tusks and restored it to its place in the universe.

4. Narasimha: A combination of man and lion, Narasimha represents another form of Vishnu. He is in the form of half-man and half-lion, having a human torso and lower body, but with a lion-like face and claws. When Prahlada, the great devotee of Vishnu was being severely tortured by his father, the demon Hiranyakasipu, Vishnu appeared as Narasimha emerging out of the pillar shown by Hiranyakasipu and killed him.

5. Vamana: The next incarnation of Vishnu is Vamana, the dwarf. This is his fifth Avatar and the first incarnation of the Second Age i.e., Treta Yuga. This is the first Avatar of Vishnu, which appears with a completely human form. He took this form to destroy the demon Bali who snatched Indra"s authority over the heavens by his power.

6. Parashurama: Vishnu took up the form of Parashurama, the sixth Avatar born as the son of the sage-couple, Jamadagni and Renuka. This avatar was to quell the arrogance of the Kshatriya rulers who harmed the sages and unprotected mortals.

7. Rama: In Hinduism, he is considered to be the seventh Avatar of Vishnu and an important manifestation of God. Vishnu came in the form of Rama to rescue the world from the demon, Ravana. Rama"s purpose was to ensure that justice and peace (dharma) ruled. He is the hero of the epic Ramayana, and he is regarded as an example of morality and virtue.

8. Krishna: Lord Krishna is the ninth incarnation of Lord Vishnu and the most popular of all his incarnations. Krishna is a deity worshipped across many traditions of Hinduism. He is the great expounder of the Bhagwad Gita. He is usually depicted as a young cowherd boy playing a flute or a youthful prince giving philosophical direction. Lord Krishna was the charioteer of Arjuna in the battle of Kurukshetra in Mahabharata.

9. Buddha: Gautama Buddha is mentioned as an Avatar of Vishnu in the Puranic texts of Hinduism. Lord Vishnu took up the avatar of Buddha, to purify Hinduism of excessive ritualism. Lord Buddha preached detachment and the middle path consisting of eight fold virtues of right views, right resolve, right speech, right conduct, right livelihood, right effort, right mindfulness and right meditation.

10. Kalki: The Kalki Avatar is the only avatar of Vishnu that is set in the future. It is believed that at the end of the present age i.e., Kali Yuga, there will be a deluge when Kalki - the tenthth and the last avatar of Vishnu, will ride forth on a horse to redeem humankind and re-establish righteousness. Riding on the back of a white horse, with a drawn sword, he will destroy the enemies of Dharma and re-establish it in all its glory.

In all the forms, Vishnu is regarded as the preserver and protector. Hinduism teaches that when humanity is threatened by chaos or evil, Vishnu will descend into the world in one of his incarnations to restore righteousness.