See L. C. Gabel, Benefit of Clergy in England in the Later Middle Ages (1929, repr. 1969); J. R. Cameron, Frederick William Maitland and the History of English Law (1961).
Homeos could have special benifits because they were seperate from the secular courts. THey did not have the same trials either.
At first, in order to plead the benefit of clergy, one had to appear before the court tonsured and otherwise wearing ecclesiastical dress. Over time, this proof of clergy-hood was replaced by a literacy test: a defendant demonstrated their clerical status by reading from the Bible. This opened the door to lay, but nonetheless literate, defendants also claiming the benefit of clergy, and in 1351 under Edward III this loophole was formalized in statute, and the benefit of clergy was officially extended to all who could read.
Unofficially, the loophole was even larger, because by tradition the Biblical passage used for the literacy test was inevitably and appropriately Psalm 51 (Psalm 50 according to the Vulgate and Septuagint numbering), Miserere mei, Deus, secundum misericordiam tuam. (O God, have mercy upon me, according to thine heartfelt mercifulness). Thus, an illiterate person who had memorized the appropriate Psalm could also claim the benefit of clergy, and Psalm 51 became known as the neck verse, because knowing it could save one's neck by transferring one's case from a secular court, where hanging was a likely sentence, to an ecclesiastical court where both the methods of trial and the sentences given were more lenient. If the defendant who claimed benefit of the clergy was particularly deserving of death courts occasionally would ask that he read a different passage from the Bible. Because most defendants were illiterate and had simply memorized Psalm 50 the defendant would not be able to establish the defense and he would be put to death.
In the ecclesiastical courts, the most usual form of trial was by compurgation. If the defendant swore an oath to their own innocence and found twelve compurgators to swear likewise to their belief that the accused was innocent, they were acquitted. A person convicted by an ecclesiastical court could be defrocked and returned to the secular authorities for punishment, but over time, the English ecclesiastical courts became increasingly lenient, and by the 15th century, most convictions in these courts led to a sentence of penance.
As a result of this leniency in the ecclesiastical courts, a number of reforms were undertaken to combat the abuse of the benefit of clergy. Henry VII decreed that non-clergymen should be allowed to plead the benefit of clergy only once: those taking the benefit of clergy, but not able to prove through documentation of their holy orders that they actually were clergymen, were branded on the thumb, and the brand disqualified them from pleading the benefit of clergy in the future. (In 1547, the privilege of claiming benefit of clergy more than once was extended to peers of the realm, even illiterate ones.)
In 1512, Henry VIII further restricted the benefit of clergy by making certain offences "unclergyable" offenses; in the words of the statutes, they were "felonies without benefit of clergy." This restriction was condemned by Pope Leo X at the Fifth Lateran Council in 1514, and the resulting controversy (in which both the Lord Chief Justice and the Archbishop of Canterbury became involved) was one of the issues that would lead to Henry VIII splitting the Church of England from the Roman Catholic Church in 1532. By the end of the 16th century, the list of unclergyable offences included murder, rape, poisoning, petty treason, sacrilege, witchcraft, burglary, theft from churches, and pickpocketing.
In 1575 a statute of Elizabeth I radically changed the effect of the benefit of clergy. Whereas before, the benefit was pleaded before a trial to have the case transferred to an ecclesiastical court, under the new system the benefit of clergy was pleaded after conviction but before sentencing, and it did not nullify the conviction, but rather changed the sentence for first-time offenders from probable hanging to branding and up to a year's incarceration.
By this point, benefit of clergy had been transformed from an ecclesiastical privilege to a mechanism by which some first-time offenders could obtain partial clemency for some crimes. Legislation in the 17th and 18th centuries further increased the number of people who could plead benefit of clergy, but decreased the benefit of doing so.
Women acquired the benefit of clergy in 1624, although it was not until 1691 that they were given equal privileges with men in this matter. (For example, prior to 1691, women could plead the benefit of clergy if convicted of theft of goods valued less than 10 shillings, while men could pray for their clergy for thefts up to 40 shillings.) In 1706, the reading test was abolished, and the benefit became available to all first-time offenders of lesser felonies.
Meanwhile, an increasing crime rate prompted Parliament to exclude many seemingly minor property crimes from the benefit of clergy. Eventually, housebreaking, shoplifting goods worth more than 5 shillings, and the theft of sheep and cattle all became felonies without benefit of clergy that earned their perpetrators an automatic death sentence.
When the literacy test was abolished in 1706, the lesser sentence given to those who pleaded benefit of clergy was increased to up to 6-24 months hard labour. Under the 1718 Transportation Act, those who pleaded benefit of clergy could be sentenced to seven years' banishment to North America. The American Revolution in 1776 disrupted the ability to apply this punishment, and with the abolition of branding in 1779, benefit of clergy was no longer an option in most cases. Although transportation shifted to Australia, this came to be done using straightforward sentences of transportation for a number of years or life. Benefit of clergy was formally abolished by Parliament in 1827. It had already been taken away from federal courts by an Act of Congress in 1790 in the United States, but it survived well into the mid-1800s in some state courts (for example, South Carolina granted a defendant benefit of clergy in 1855) and may even remain technically available in some states today. While many states have abolished clergy by statute or judicial decision, in some it has simply fallen into disuse without formal abolition.