Step 1: Understanding the Question:
The question asks for the historical date of the Kalinga War.
Step 3: Detailed Explanation:
The Kalinga War was a pivotal event in ancient Indian history. It was fought between the Mauryan Empire under Emperor Ashoka and the state of Kalinga (modern-day Odisha). The war is famously known for its brutal scale and for profoundly impacting Emperor Ashoka, leading to his conversion to Buddhism and his subsequent embrace of non-violence (Dhamma-vijaya).
Historical records, particularly Ashokan edicts, confirm that the Kalinga War took place in 261 BC.
Step 4: Final Answer:
The Kalinga War was fought in 261 BC.