Jean-Jacques Rousseau is well known for his love of the ancients. His use of examples from Sparta and republican Rome emphasized what he found lacking in modern times. This article attempts to establish how Rousseau's views on the ancients are related to his religious-political thought, particularly as it relates to his description of citizen religion in the last chapter of the Social Contract. While Rousseau admired many aspects of citizen religion, he rejects it for two reasons: reasons of humanity in the Geneva Manuscript and reasons of self-interest in the Social Contract. This article attempts to understand how the two can be reconciled through the view of citizen religion's contribution to patriotism and fanaticism.