The Kalinga War and Repentance
Ashoka launched a large-scale war to annex the state of Kalinga, and according to his own edict inscriptions this war caused more than a hundred thousand deaths and more than a hundred and fifty thousand captured; having witnessed the horror of the battlefield he was deeply stricken with remorse and grief, thereafter embraced Buddhism, and declared "conquest by dharma" in place of conquest by force as the fundamental principle of his rule — a record of self-reflection exceedingly rare among ancient monarchs.