When earth’s rulers and citizens were taking pride in torturing life forms, Vishnu felt that it was time to teach them about compassion and ahimsa (non-violence) towards both humans as well as animals. Accordingly, he incarnated as Buddha in Kapilvastu in 6th century BCE.
Because it had been prophesized that Prince Siddhartha (Buddha’a name in early life) may give up the material world one day, his father tried his best to keep him away from spirituality and distress. But at the right moment, simple observations of human suffering (a sick person, an elderly, and a corpse) led him to renounce his kingdom and family, and he began his search for realization. One could argue that he was already detached (from birth) and only needed a slight initiation. He began his search with philosophical learning, asceticism, and travels to religious places, but these alone could not give him what he was looking for. Finally, meditation under a tree worked, and he turned into the “enlightened one” in Bodhgaya in present-day Bihar.
For the liberation of the commoner, Buddha established and propagated the eightfold path, which involved perfection in understanding, thought, speech, action, livelihood, effort, awareness, and concentration. Interestingly, from a Hindu perspective, there is a lot in common between this path and the mental training and cleansing needed to succeed in Karma Yoga or Jnana Yoga.
Fun fact: Astrologically, Buddha’s incarnation is connected to Mercury, the planet of intellect and communication, and symbolizes intellectual perfection.