Some readers are unfamiliar with this phrase. It was used by S Edmund Campion in his Rationes Decem, printed surreptitiously at Stonor House near here and as surreptitiously put on all the seats to be picked up by the University as it gathered for the Act in June 1581. See my paper in Luther and his progeny, Angelico Press, 2017.
It refers to the rumour that John Calvin had been branded after being convicted of homosexual acts. I have no idea whether this is true; I believe the contrary view is that the confusion arose because another inhabitant of Geneva with the same name was thus branded at around the same time. Perhaps an expert could sort this out.
In ancient Rome, runaway slaves, when captured, were branded HFE (Hic Fugitivus Est).
In this country, those convicted of (any) sexual offences against others are required to sign something called the Sex Offenders' Register. This sounds a truly fearful penalty.
But perhaps the branding system would be an even more effective deterrent.
It could be left to the judge or jury to determine whether or not this should be done under a general anaesthetic.
Not really. I'm joking. Who am I to judge?