Early Christians labeled any schismatic an Antichrist

Evidence

But the Antichrist is also he who denies that Christ is God. He is therefore the contrary of Christ. Therefore all who depart from the church and who cut themselves off from the unity of the faith are Antichrists. — John V. Tolan, Saracens, 108

Categorization

• XREF: The logic that ‘denier of Christ = Antichrist = enemy of the church’ parallels later crusade-era rhetoric that legitimizes attacking religious others. — connects to: Antichrist folklore makes every new supranational body a suspected Antichrist vehicle — Michael Barkun, A Culture of Conspiracy: Apocalyptic…, 257