[Triarii]

Thread diversion alert!
On the legal aspects of duelling (I have a number of books on this in the C16th / C17th and am expanding my interest into the roots of the duel in English law and the insinuation of the Italian duello into civil society - some of the latter makes for very dull reading indeed);

Benefit of clery gained you exemption from secular courts, originally if you were clergy, initally demonstrated by the tonsure and your garb, later (from the C14th) by reading, as from the early medieval period, only the clergy were literate. Indeed, teaching people who were imprisoned who were not clergy, to read, was an offence. Being able to read originally got you moved to an ecclesiastical court.

The reading test was used for quite a while and became a part of English Common Law, surving beyond the Reformation. Women could claim benefit of clergy in 1624 or 1629 (not clear) but didn't get full equality in this until 1691, showing that the warping of the original intent was accepted.

Over time (I can't identify the precedent), a rather appropriate opening line from Psalm 51 - one of the penitential psalms - came to be the standard reading material and became known as 'the neck verse':
“Miserere mei Deus secundum misericordiam tuam iuxta multitudinem miserationum tuarum dele iniquitates meas.” or in English;
“Have mercy on me, O God, according to your steadfast love; according to your abundant mercy blot out my transgressions”

People were known to rehearse the neck verse by rote in an attempt to claim the benefit of clergy.

The judge would ask in Latin if the defendent could read or not and the church representative would respond in Latin that 'he/she reads like a clerk'. In this case you could be whipped or fined. At some period during Henry VIIs reign, the punishment was branding on the thumb for non-clergy, as you could only get away with this once and hence the brand revealed any previous offence, but I'm having trouble with a reliable source for this.

Henry VIII extended branding to the clergy, but Edward VI abolished this and allowed Peers to claim the benefit more than once, which meant no branding (which may be the issue referred to in Byrons case), and both excepted the following from benefit of clergy: murder (in simple terms, if premediatated), poisoning, burglary, highway robbery, and sacrilege. This list was progressivley lengthened over time. The nobility (ie Peers) were not to be branded and were to be acquited for any offence, except murder and poisoning, even if they were illiterate. Hence the importance of 'hot blood and 'cold blood' in duelling and whether it was murder or manslaughter.

Benefit of Clergy was done away with acts passed in 1823, 1827 and 1841.