Why did Ashoka the Great turn to the teachings of the Buddha?

He never wanted to repeat the devastation caused during one of his conquests.

Ashoka turned to the teachings of the Buddha because he felt that the life he was living wasn't right. He thought that there had to be some sort of divine power and/or eternal balance and harmony with nature. That was when he adopted the ideas of Buddhism, and practiced them. This consolidated his power by making him more respected.