The Concept of Innocent Until Proven Guilty Dates to Roman Law

While the presumption of innocence is a pillar of modern justice, its intellectual blueprint was drafted thousands of years ago. In ancient Rome, a sophisticated legal framework began to take shape, moving away from arbitrary judgment and toward evidence-based reasoning. This evolution was captured in the influential Digest of Justinian, a 6th-century codification of Roman law, which included the work of the 3rd-century jurist Paulus. He articulated the core tenet: 'ei incumbit probatio qui dicit, non qui negat,' establishing that the responsibility for providing proof falls upon the person making the accusation, not the person issuing a denial.

This principle was a radical departure from other ancient and medieval practices where an accusation alone could require the defendant to undergo a trial by ordeal or combat to prove their innocence. The Roman approach placed the onus squarely on the accuser, demanding they substantiate their claims with facts. Although this legal safeguard was largely lost in Europe during the Middle Ages, the concept was rediscovered and championed by Enlightenment thinkers. It profoundly influenced the development of English common law and was later enshrined in foundational documents like the U.S. Constitution, ensuring that an individual's liberty is protected from unsubstantiated claims.