The Mauryan Empire declined due to several factors: 1. Weak rulers led to decentralization of the highly centralized administration, as regional rulers declared independence. 2. A weakening of the central administration coupled with the vast size of the empire made it difficult to maintain control over distant regions. 3. The monarchical system relied on personal loyalty to the king rather than loyalty to the state, undermining stability when weak rulers came to power. 4. Ashoka's policies of non-violence and pacifism, as well as efforts promoting Buddhism, weakened the military and overburdened finances, making the empire vulnerable to external attack.