In 2013, Pope Francis became the first Catholic leader to call for "sincere and rigorous" interbelief dialogue with atheists, both to counter the assertion that Christianity is necessarily an "expression of darkness of superstition that is opposed to the light of reason," and to assert that "dialogue is not a secondary accessory of the existence of the believer" but instead is a "profound and indispensable expression ... [of] faith [that] is not intransigent, but grows in coexistence that respects the other."