What set of written laws was rome's first, and applied to both the rich and the poor?

The Twelve Tables record the laws pertaining to procedures for courts and trials, the rights of the father over the family, inheritance and legal guardianship, possession and acquisition, land rights, torts and delicts, public law, sacred law and two supplements to the law. Initially there were only 10 tablets, or tables. The plebeians were not entirely appeased by these ten. Prior to the Twelve Tables, all Roman law was unwritten and carefully guarded by a small group of patricians, leading to the plebeians being tried in a court of law without knowing what their rights were. The Twelve Tables did not amend Roman law; they simply put down in writing what the current laws were. Later written changes in Roman law effectively superseded the laws of the Twelve Tables even though the Tables were never formally abolished.