Excerpts from Books and Wikipedia
"Ashoka waged a destructive war against the state of Kalinga (modern Odisha), which he conquered in about 260 BCE. In about 263 BCE, he converted to Buddhism after witnessing the mass deaths of the Kalinga War, which he had waged out of a desire for conquest and which reportedly directly resulted in more than 100,000 deaths and 150,000 deportations. He is remembered for the Ashoka pillars and edicts, for sending Buddhist monks to Sri Lanka and Central Asia, and for establishing monuments marking several significant sites in the life of Gautama Buddha." [Wikipedia]
"'Afterwards,' the Edict continues, 'I felt remorse. The slaughter, death and deportation of the people is extremely grievous . . . . And weighs heavy on the mind.' . . . 'I very earnestly practiced dhamma, desired dhamma, and taught dhamma,' the Kalinga Inscription says, and a little later in the same Edict, 'Any sons or great-grandsons that I may have should not think of gaining new conquests . . . Delight in dhamma should be their whole delight, for this is of value in both this world and the next.'" [Bauer, Ancient World, p. 611]