Defense of Athanasius and the Nicene Faith
The central act of Liberius's episcopate, as the sources record it, was his defense of Saint Athanasius of Alexandria, the foremost opponent of Arianism, against the demand that he be condemned. Liberius upheld the acquittal of Athanasius and treated the Nicene faith as the standard of orthodoxy. When the Council of Milan in 355 was pressed by imperial command to abandon Athanasius, Liberius protested, and his refusal to sign brought upon him the emperor's anger and ultimately his banishment.