A more thorough explanation:

The Twelve Tables is the earliest surviving legislation enacted by the Romans, written on 12 tablets in the 5th century B.C.

The Tables set out many rights and duties of Roman citizens, including debtors' rights, family law, wills, torts, civil procedure, and some public law.

They substituted a written body of laws, easily accessible and binding on all citizens of Rome, for an unwritten usage accessible to only a few.

The law of the Twelve Tables was also known as the Lex Duodecim Tabularum.

For example, the Twelve Tables established the right of a debtor to be released from his debt after three years of unpaid interest.

The Twelve Tables continued to be recognized for many centuries as the fundamental law of the Romans.

The Twelve Tables were important because they established a written body of laws that was accessible to all citizens of Rome. This replaced the previous unwritten laws that were only accessible to a select few. The laws covered a wide range of topics, including debtors' rights, family law, wills, torts, civil procedure, and some public law. The example of the debtor's right to be released from debt after three years shows how the laws protected the rights of citizens. The Twelve Tables continued to be recognized as the fundamental law of the Romans for many centuries.