As Roman society evolved, so did cult to emperors: both proved remarkably resilient and adaptable. Until its confrontation by fully developed Christian orthodoxy, "Imperial cult" needed no systematic or coherent theology. Its part in Rome's continued success was probably sufficient to justify, sanctify and "explain" it to most Romans. Confronted with crisis in Empire, Constantine matched the Augustan achievement by absorbing Christian monotheism into the Imperial hierarchy. Cult to emperors was not so much abolished or abandoned as transformed out of recognition.