The Origins and Legacy of Roman Law

Sara Santos-Vigneault
Oct 20
4 min read

Written by: Sara Santos-Vigneault

Date: October 20, 2025

A group of men in Roman togas close in on a central figure, Julius Caesar, who recoils in shock and anguish. Set within a grand marble hall adorned with statues, the air brims with betrayal and violence. The tension of the moment is palpable, as daggers are raised and urgency fills the dramatic scene. — Image by **Gordon Johnson** from Pixabay

Origins of Roman Law

In the Regal period (753 to 509 BCE), Rome was ruled by kings. The origins of Roman law can be traced to this era, when law was unwritten and derived from ancestral custom (mos maiorum) and religious ritual. It was preserved by priests and interpreted by the king, who served as both ruler and high priest. Later tradition credited monarchs like Numa Pompilius with embedding religious offices into civic life, and Servius Tullius with linking legal duty to military service through property-based classifications.

Although partly legendary, these accounts reflect how Romans understood law as rooted in custom, religion, and royal authority. Justice was controlled by elites, and disputes were resolved case by case. This unwritten system created stability but left ordinary Romans vulnerable. That vulnerability ultimately led to calls for codified law in the Republic.

Timeline of Roman Legal Milestones

Approx. Date	Legal Development	Significance
753 BCE	Regal period begins	Rome ruled by kings. Law based on mos maiorum (ancestral custom) and priestly authority, forming the cultural foundation of later traditions.
509 BCE	Republic established	Monarchy abolished. Magistrates and patrician elites control law and interpretation.
450 BCE	The Twelve Tables	First codified Roman law, published in the Forum to restrain patrician judges and ensure accessibility.
367 BCE	Licinian-Sextian laws	Expanded plebeian rights, limited elite landholding, and required one consul to be plebeian.
304 BCE	Gnaeus Flavius publishes legal calendar	Broke the priestly monopoly on legal procedure and gave citizens broader access to law.
195 BCE	Repeal of Lex Oppia	Women’s protests led to repeal of sumptuary law that restricted wealth and adornment.
44 BCE	Assassination of Julius Caesar	Caesar’s dictatorship tested the limits of Republican law. His death exposed constitutional fragility and led to imperial legal transformation.
212 CE	Edict of Caracalla	Granted citizenship to all free men in the Empire, expanding the reach of Roman private law.
438 CE	Theodosian Code	First systematic collection of imperial constitutions. Provided clarity across the empire.
529–534 CE	Justinian’s Corpus Juris Civilis	Comprehensive codification including the Code, Digest, Institutes, and Novels. Formed the basis for modern civil-law systems.

Origins of Codified Roman Law

When the Republic was founded in 509 BCE, patrician magistrates controlled the interpretation of law. In response, plebeians demanded transparency. The Twelve Tables, created around 450 BCE, became Rome’s first written code. They were displayed publicly in the Forum and covered contracts, property, inheritance, family structure, and punishments.

Religion continued to shape legal practice. Pontiffs retained authority over procedures and court calendars. That changed when plebeian pressure, combined with Gnaeus Flavius’s publication of legal materials in 304 BCE, expanded public access to the law.

Female Influence in Early Roman Law

Roman women were subject to patria potestas, the legal authority of the male head of household, and could not hold public office. Nonetheless, they influenced the law through inheritance, family networks, and collective action.

The Twelve Tables allowed daughters and widows some inheritance rights, although often under guardianship. Over time, the decline of manus marriage gave women greater control over their property.

Influential figures such as Cornelia, the mother of the Gracchi, shaped public life through family. In 195 BCE, Roman women protested in the streets to demand the repeal of the Lex Oppia. This sumptuary law, enacted during wartime, limited women’s use of wealth and adornment. Their successful campaign led to the law’s revocation and remains a powerful example of female political influence in a male-dominated legal system.

Ancient Roman stone street with tall, sunlit brick ruins on each side. The surface is uneven with small stones, creating a rustic, historic feel. — Image by pascal OHLMANN from Pixabay

Julius Caesar and the Strain on Republican Law

By the 1st century BCE, the Republic’s legal institutions were increasingly unstable. Julius Caesar leveraged this instability to accumulate extensive powers through military victories and political alliances. His appointment as dictator perpetuo concentrated religious, political, and legal authority in one man.

This consolidation of power was widely viewed as tyrannical. His assassination in 44 BCE sparked a constitutional crisis. The Republican legal system had no effective checks to contain his rise.

Following his death, Augustus rose to power and created the Principate. Though it preserved the outward form of the Republic, real legal authority now rested with the emperor. Imperial decrees and judicial rescripts became the primary sources of law, shifting Rome toward an autocratic legal model.

The Legacy of Roman Legal Development

The Twelve Tables set a precedent for transparent, written law. Reforms such as the Licinian-Sextian laws expanded plebeian access to office. The publication of court procedures by Gnaeus Flavius eroded the priestly monopoly on legal knowledge. Although excluded from formal roles, women influenced inheritance, household law, and even legislation.

Caesar’s dictatorship revealed the weakness of the Republic’s constitutional protections.

The Principate solidified imperial control over lawmaking. Later codifications such as the Theodosian Code (438 CE) and Justinian’s Corpus Juris Civilis (529 to 534 CE) brought together centuries of laws, commentary, and precedent. Justinian’s system became the cornerstone of the civil-law tradition that still dominates many legal systems around the world.

Roman law evolved from unwritten traditions to a sophisticated codified system. From the kings who united religion and justice, to plebeians demanding legal transparency, to women influencing law through protest, Roman legal history reflects continuous adaptation. The Corpus Juris Civilis ensured that Roman legal thought would influence Western civilization long after the empire had fallen.