The Emergence of Common Law
William Blackstone's Commentaries on the Laws of England became the playbook for America's Founders. It broke down legal chaos into four categories:
- Rights of persons
- Rights of things
- Private wrongs (torts)
- Public wrongs (crimes)
It preached that life, liberty, and property were pillars of a person's rights. Those "Rights of Englishmen" appealed to American colonists, who incorporated concepts like due process, attorney-client confidentiality, and equality before the law into the American Constitution.
The Roman influence on English law was minimal during the Anglo-Saxon era, with customs favored over codes. The Norman Conquest in 1066 brought some Roman ideas back. Christianity and Canon law also introduced Roman law concepts. Henry II incorporated Roman law into his reforms, though the legal fabric remained distinctly English.
Ranulf Glanvil's treatise (1187-1189) outlined legal procedures introduced by Henry II, including land laws, writs, and jury trials. Henry II consolidated courts, initiated jury trials, and curbed the Church's independence.
The Magna Carta of 1215 laid groundwork for legal concepts like due process and habeas corpus, though class distinctions remained. King John's mismanagement led to its creation.
Henry de Bracton's treatise during Henry III's reign codified common law, making it systematic. Henry II's reign marked the birth of Common Law, with permanent courts in Westminster standardizing rules.
The Grand Jury system, introduced in 1166, required criminal accusations to be approved by twelve lawful men. Possessory assizes strengthened property law, allowing land reclamation through Royal Writs. These reforms intertwined legal customs with royal authority, setting the stage for a legal system that would later influence American law.

Common Law Principles and Procedures
Common Law's core is judicial precedent, or case law. This principle of "stare decisis" ensures consistency in rulings. It contrasts with Civil Law systems, which rely on legal codes with less room for judicial interpretation.
Common Law's reliance on written documentation, including royal writs, case opinions, and legal textbooks, creates a detailed legal framework. The writ of Mort d'Ancestor and writ of Novel Disseisin moved property disputes from local feudal lords to royal courts.
Trial by jury, enshrined in the Sixth and Seventh Amendments, allows citizens to participate in court decisions. Civil trials in American courts use the "preponderance of evidence" standard, reflecting community values.
Common Law balances adaptability with tradition, providing consistency and flexibility. It binds us to past wisdom and community values, standing as a guardian of justice and liberty.

Influence of Roman Law
Roman law significantly influenced English Common Law, affecting the American legal system. Emperor Justinian's Institutes in the 6th century provided a comprehensive legal guide.
The Norman Conquest of 1066 reintroduced Roman ideas to England. Christianity and Canon law acted as conduits for Roman legal concepts.
Ranulf Glanvil's 12th-century treatise systematized local customs with Roman influence. Henry de Bracton's 13th-century work further codified English common law, incorporating Roman legal principles.
Ecclesiastical scholars trained in Canon and Civil law integrated Roman concepts of justice, equity, and legal reasoning into English Common Law.
The Roman influence on English Common Law provided a foundation for the common law traditions later adopted by American Founders. They recognized the value of combining ancient legal principles with societal needs, anchoring them in Western legal philosophy. The American legal system derived its pragmatism, adaptability, and commitment to individual rights from this intertwined legacy.
Magna Carta and Its Legacy
Magna Carta, signed in 1215, laid the groundwork for constitutional government. Key clauses like 39 and 40 established principles of due process, fair trials, and equal justice. Clause 61 introduced checks on royal power, foreshadowing modern checks and balances.
These concepts influenced later legal developments, including:
- Habeas corpus
- Limitations on government authority
The Magna Carta's emphasis on rule of law and individual rights resonated with America's Founders as they crafted the Constitution and Bill of Rights.1

Common Law's Influence on American Founders
The Founding Fathers drew heavily from English Common Law when creating America's legal system. They particularly valued William Blackstone's Commentaries, which explained legal principles in accessible terms.
Key Common Law concepts embedded in the Constitution include:
- Trial by jury (Sixth and Seventh Amendments)
- Due process (Fifth and Fourteenth Amendments)
- Habeas corpus
- Judicial precedent (stare decisis)
The Founders adapted these principles to fit the new republic while maintaining their core focus on individual rights and limited government power. This synthesis of English legal tradition and American innovation formed the basis of U.S. constitutional law.2
Trial by Jury: A Cornerstone of Liberty
Trial by jury evolved from ancient practices in Greece and Rome to become a key feature of English Common Law. The Magna Carta explicitly protected this right for free men.
"The heart and lungs of liberty." – John Adams on jury trials
America's Founders saw jury trials as essential to liberty and democracy. The Sixth Amendment guarantees criminal jury trials, while the Seventh covers civil cases.
Juries allow citizens to participate directly in the justice system, acting as a check on government power. They ensure that legal outcomes reflect community standards. Even today, jury service remains one of the main ways ordinary people engage with the democratic process.3

In summary, the American legal system is deeply rooted in English Common Law principles. The Founding Fathers adapted these ideas to create a framework prioritizing liberty, justice, and rule of law that continues to shape the nation.