Espionage was popular throughout human history, as it helped gather intelligence on one's enemies and sometimes also to enhance one's own power using those data. Sun-Tzu himself, the most famous strategist of the ancient world, did not ignore this aspect of politics and warfare, and neither did Chandragupta Maurya, the founder of the Maurya Empire in India. Western Civilizations weren't any less enthusiastic about the espionage: it played a large role in Egypt, Greece, Israel and Rome. Perhaps the most iconic spies of the old days were the kunoichis from Japan, who used their social skills and martial training to infiltrate the enemy.