Chandragupta Maurya, the founder of the Maurya Empire in ancient India, is historically known for his strategic use of intelligence and military tactics to address his fears of enemies. One of the most effective reactions to his fear of opposition was to set up a large network of spies. This intelligence network allowed him to gather crucial information about potential threats and the movements of rival kingdoms, helping him make informed decisions in both peace and war.
While he did engage in military campaigns and consolidation of power, his emphasis on espionage was key to his success in establishing and maintaining his empire. Thus, among the options provided, the correct answer would be to set up a large network of spies.