You’re right, it was an absolutely gruesome punishment. That’s why it was reserved for crimes like treason. To understand the mentality around it, we also have to look at executions as a whole.
Until relatively recently, executions were basically an excuse to have a big Sunday picnic. The public would get dressed up nicely and head out to watch them hang that weeks criminals. Jail as a concept didn’t really exist until the 1800s, and even then, was more a “workhouse” that was supposed to teach the poor “skills” and “discipline” that would help them get a job (by doing things like walking on massive wheels and picking fibres out of ropes—that’s what ruined Oscar Wilde’s hands). That left fines and execution as punishment, and there wasn’t really any moral dilly dallying about execution as a result.
Back to being hung drawn and quartered specifically: like I said earlier, it was reserved for the absolute worst crimes, mostly treason and regicide. The whole point of it was to dissuade others from acts that destabilized the entire government. Real instances of treason and attempted regicide were few and far between, and so being hung drawn and quartered wasn’t actually a common punishment. Part of the reason we hear about it so much is something called matchbooks, which basically were very short pamphlets circulated among the semi-literate population of the most salacious crimes (kind of like tabloids), partly to entertain and partly to act as a teaching device. Incidentally, that’s also why we have so many supremely graphic accounts of witch burning, which also was actually fairly rare.
The original concept of jails was a reactionary development to executions, and as they developed, people like Charles Dickens made cases for reform rather than revenge, which reduced the number and importance of executions.
If you’re looking for additional reading on the subject, all of Britain’s court archives for felony trials from the 1600s to the early 1900s are available for free online reading, and they have an excellent search function that allows you to specifically pull up cases about treason etc. They can help you get a better feel for the mood of the court and the public in cases that resulted in a verdict of being hung drawn and quartered.
It was a very grim punishment. "you will be hanged by the neck and cut down alive, your body cut open and your bowels burnt before your face...". It seems a very strange thing for people who were, after all, reading Bible verses about forgiving your enemies and loving one another .There were, however, motivations for it.
First was the very old idea of punishments as equivalents of crimes. Law codes of the early periods ( like the Code of the Burgundians, Code of Hammurbi, etc.) read like lists of prices, and higher prices for crimes committed against important people: e.g. for wounding the ox of a peasant, one silver piece, for wounding the ox of the king, one gold piece. Treason was considered not only an offense against the king, but because the king was at the top of the divine order of things, even an offense against God. So, it was felt that the equivalent punishment should be extreme. Maybe nothing expresses the outrage at both the crime and heresy of treason better than the sermon John Donne preached on the subject of the Gunpowder Plot in 1622. Donne was no longer the deep poet, by then had become very much the Anglican priest, and his sermon laid out in page after page how much the offense against the king was an offense against God. And, notes Donne, if they were ready to tear and rend and burn the bodies of the king and members of Parliament, shouldn't the bodies of the traitors themselves be torn, rent, and burnt? Something about heresy seems to have really worked the 17th c. mind. ... Later, during the Commonwealth, the Rump Parliament would devote days to debating what James Nayler, the Quaker, should get as commensurate a punishment for blasphemy...eventually deciding to have him whipped, pilloried, his tongue bored with a red hot iron, and then have him put to hard labor.
Second was the notion of punishment as deterrence. This is, again, a very old idea, and a very intuitive one- if somebody is punished very dramatically and severely for a crime, other possible criminals should be deterred from committing the same crime. Punishments were expected to be witnessed, and memorable. The executioner of Nuremburg Jacob Schmidt listed many such in his matter-of-fact diary of the later 16th c., like riding with a woman convicted of murders , tearing at her with red-hot tongs on her way to the gallows. One edition of a popular collection of crime stories from the 18th c., the Newgate Calendar or Bloody Register, had a frontspiece of a mother with her son at her knee , pointing out the window toward a distant hill where the body of a criminal dangles from a gibbet. Punishments were to set an example, to warn off possible malefactors from committing crimes. .
Eventually, however, it was noticed in the 18th c. that, really, punishments did not seem to deter crime as much as it seemed they should. If the law allowed a young child of 10 to be hanged for stealing a loaf of bread, in 1750, it seemed boys were still, nonetheless, stealing bread. It also began to seem less important for the condemned to suffer a slow and painful death - by the time "cruel and unusual punishments" were banned in the US constitution, they were on their way out in most European countries anyway. England had started trying out a novel public agency : the police. It turned out to be a more effective way of reducing crime.
But public executions were still thought appropriate . When David Tyrie was convicted of treason, for conspiring with the French in 1782, he was the last person in England to be hanged drawn and quartered. He was allowed to hang for more than 20 minutes, however: so the grisly stuff that followed was likely to have been, well, details. There also remained the idea of not letting the corpse of the condemned have an honorable burial: when the practice of gibbeting the corpse went out, there seemed to be a fad to have it turned over to medical men, to be dissected.
John Donne:A Sermon upon the Fifth of November 1622
