Physical conversion markers were read as impending apostasy by Christian polemicists

Evidence

The aged Avernus went so far as to have himself circumcised, surrendering his old, tough foreskin to the surgeon’s knife. This is accommodation gone too far: for Samson it is a prelude to apostasy; for Alvarus it was the mark of the Antichrist. — John V. Tolan, Saracens, 546

Categorization

• ADDENDUM: Enriches immodesty-article theme: body marking (circumcision) as the threshold act that collapses group identity — analogous to dress as boundary signal.
• SHARE: Niche detail for a medievalist friend — adult Christian circumcision as court accommodation, read as Antichrist-mark by Alvarus.