Ashoka attacked to capture the state of Orissa in 261 BC. and got victory but almost one lac people were killed in this battle. He started hating from battles after this incident and decided not to fight any further battle.
After conquering most of the regions of India and merging them into Maurya empire. when Emporer Ashoka attacked Kalinga, the people of Kalinga chose to fight. against Emporer Ashoka for their freedom instead of surrendering. The war that happened was not equally competitive. The small and un-experienced army of Kalinga was easily getting defeated. by Ashoka’s army which was huge and hardened with many battles. So to protect their self-respect and freedom. to support army of Kalinga, their ladies and children too fought with them. In the insanity to achieve victory. Mauryan army could not make out any difference among children or females. and those who came in front of the Mauryan army were brutally killed. After, approximately, one lakh people of Kalinga poured their blood. when all swords went to their cases. whole of Kalinga had become almost a crematorium.
After war, Ashoka went to have a look on his victorious presentation. he could see many funeral pyres burning on the battle field. For the first time on the battlefield, Ashoka saw dead bodies of innocent children and females. Reflection of wounded soldiers and weeping relatives of dead soldiers made Asoka shaken from inside. Always a victorious Ashoka, for the first time saw the other side of the war. which was many a times terrible than momentary happiness of his victory. For the first time Ashoka realized the violence in his lifetime, he had done to become a world champion. And from that very moment, as a part of repentance. he left violence and decided to walk on the path of non-violence.
impressed with the principles of non-violence. Ashoka adopted Buddha religion to walk on the path of non-violence. And he dedicated his total power and wealth in promotion of Buddha religion and non-violence.