Kalinga was conquered by his Sacred and Gracious Majesty when he had been
consecrated eight years. 150,000 persons were then carried away captive, 100,000
were slain and many times that number died... Thus arose his Sacred Majesty's
remorse for having conquered the Kalingas, because the conquest of a country
previously unconquered involves the slaughter, death, and carried away captive of the
people.


Ashoka in History of Modern India by Percival Spear


Why was Ashoka remorseful about the campaign against Kalinga?


What did the conquest of Kalinga cause Ashoka to realize about the nature of war?