This feudal right was established around 1000 AD. At the time, it was a reasonable law. Unfortunately it benefited the rich and powerful, so it was extended over nine centuries.
When the heriot started in England, serfdom was in full swing. One of the duties of a serf was to serve in his lord’s army. He could serve the army better if he was in a good suit of armor, but being a serf, he found armor hard to come by. Typically the lord would provide armor, or even a horse. When the serf died, in battle or otherwise, the armor or horse would go back to the lord, and presumably, out to the next serf who needed it.
Over time, the heriot changed. It stopped being about the distribution of necessary goods and started being a way of screwing over the poor. By the 1300s, the heriot demanded that, upon his death, a person tied to the land of a lord owed the lord his or her most valuable possession. This could be clothing or goods, but it was most often the person’s most precious head of cattle, or their finest horse. This wasn’t the only claim on a tenant’s legacy. The “mortuary,” another law, specified that the rector on a piece of land got the second-best animal.
What counted as the best animal? There were all kinds of specifications about what kind of animal was acceptable. Apparently a hen had to be accepted by a lord, provided it could, “clear the garden fence or jump upon a stool.” There were also ways to modify the right. As livestock and used clothes became less useful and cash became more so, an independent judge could value the tenant’s most precious possession and the lord could claim the right to it in cash. So that was progressive.
As more time passed, the right fell out of use. Occasionally it popped up. In the late 1800s one man bought land owned by Oxford University and still subject to the old laws. The man was a collector of race horses and had to purchase the “freehold” or exclusive possession of the land to keep from having to will his best horses to the university. Still, the law lingered on in England until the 1920s, when the comprehensive reform of the Law of Property Act of 1922 made the heriot obsolete once and for all.