Roman religion was largely what determined "Romanness". The Christian refusal to sacrifice to the Roman gods was seen as an act of defiance against this cultural and political characteristic and the very nature of Rome itself. MacMullen quotes Eusebius as having written that the pagans "have thoroughly persuaded themselves that they act rightly and that we are guilty of the greatest impiety". According to Wilken, "The polytheistic worldview of the Romans did not incline them to understand a refusal to worship, even symbolically, the state gods.". According to MacMullen, this meant Christians were "constantly on the defensive", and though they responded with appeals to philosophy and reason and anything they thought might weigh against "ta patria" (the ancestral customs), they could not practice Roman religion and continue fealty to their own religion. Abel Bibliowicz says that, amongst the Romans, "The prejudice became so instinctive that eventually, mere confession of the name 'Christian' could be sufficient grounds for execution".