American law didn’t start from a blank page. Most of its structure — the jury, the idea of legal precedent, due process itself — was inherited from England, reworked over roughly a thousand years before a word of the U.S. Constitution was written. Here’s the short version of where it came from.
Before 1066: Local Custom, Not Written Law
Early medieval England had no central legal system. The Anglo-Saxons organized the countryside into shires (counties), each divided into “hundreds” — groupings of roughly 100 families — and those into “tithings” of about 10 families, who were collectively responsible for keeping order among themselves. The chief law-enforcement official of a shire was the shire-reeve, a title that contracted over time into “sheriff.”
Crime, in this system, was treated largely as a private matter between the offender and the victim’s family, settled through compensation. If no payment could be agreed on, families sometimes pursued a blood feud instead — one reason a centralized system of courts and enforceable judgments eventually looked like an improvement to almost everyone.
1066: The Norman Conquest and the Birth of Common Law
When William, Duke of Normandy, defeated King Harold at the Battle of Hastings in 1066 and took the English crown, he declared that all land — and all land-based rights, including the administration of justice — belonged to the king. To keep the local courts under royal control, William created traveling royal judges, called an Eyre, who rode circuit through the country hearing disputes and collecting the crown’s share of forfeited property.
As these judges resolved case after case, their decisions started forming a consistent body of law that applied across the whole country rather than varying town to town — hence “common” law, and because it built up case by case, it’s also called case law. The principle that a later court should generally follow an earlier court’s decision on the same question — stare decisis — comes directly from this period, and it still governs how American appellate courts operate today.
1215: The Magna Carta
In 1215, England’s powerful landholders, worn down by King John’s heavy taxation, rebelled and forced him to sign the Magna Carta. Its purpose was narrow at the time — settling specific disputes between the king and his nobles by placing limits on royal power — but the principle it established, that even a king is bound by law, became the foundation of what later developed into due process of law: the idea that government can’t take a person’s life, liberty, or property without a fair legal procedure first.
Trial by Ordeal, and How the Jury Replaced It
Before there were juries, disputed criminal accusations in England were often settled by ordeal — the accused might be made to carry a red-hot iron or plunge a hand into boiling water, on the theory that divine intervention would protect an innocent person from a wound that wouldn’t heal. A related practice, trial by combat, let the accused challenge an accuser to a duel (or hire a champion to fight in their place).
This system fell apart in 1215, the same year as the Magna Carta, when the Catholic Church’s Fourth Lateran Council barred priests from participating in trials by ordeal. Without clergy to bless the proceeding, English courts needed a new method, and they adapted one already used for a different purpose: local groups of knights had long been summoned to testify to a royal inquest about land boundaries and tax valuations. By 1219, these same sworn panels — jurati in Latin, the root of “jury” — began being used to decide criminal accusations too, first as witnesses reporting what they personally knew, and by the 1300s as the actual deciders of fact.
A landmark moment for the jury’s independence came in 1670, in Bushell’s Case: a London jury acquitted William Penn (the future founder of Pennsylvania) of unlawful assembly, and when the judge tried to punish the jurors for refusing to convict, an English court ruled that jurors could not be penalized for their verdict. That principle — a genuinely independent jury, answerable to no one for its decision — crossed the Atlantic intact and sits behind the right to a jury trial in the Sixth Amendment today.
1776 to 1789: From Colonies to Constitution
By the mid-1700s the thirteen colonies had grown weary of being governed from London, and in 1774 they sent delegates to the First Continental Congress in Philadelphia. The Declaration of Independence, drafted mainly by Thomas Jefferson, was adopted on July 4, 1776 — though full independence wasn’t won until 1781.
The first attempt at a national government, the Articles of Confederation (1781), deliberately kept the national government weak: it couldn’t tax citizens directly, only request contributions from the states, which it also had no power to enforce. Within a few years this left the young country broke and unable to solve basic problems, and in 1787 delegates met in Philadelphia — ostensibly to revise the Articles — and wrote an entirely new Constitution instead. It was ratified in 1788 and took effect in 1789, with the Bill of Rights, the first ten amendments, added in 1791.
Everything covered in how the U.S. legal system works — federalism, the court structure, the balance between statute and common law — traces back to decisions made in this narrow, high-pressure window between 1787 and 1791.