The Twelve Tables allegedly were written by 10 commissioners (decemvirs) at the insistence of the plebeians, who felt their legal rights were hampered by the fact that court judgments were rendered according to unwritten custom preserved only within a small group of learned patricians. Beginning work in 451, the first set of commissioners produced 10 tables, which were later supplemented by 2 additional tables. In 450 the code was formally posted, likely on bronze tablets, in the Roman Forum.
The written recording of the law in the Twelve Tables enabled the plebeians both to become acquainted with the law and to protect themselves against patricians’ abuses of power.
The Twelve Tables were not a reform or a liberalizing of old custom. Rather, they recognized the prerogatives of the patrician class and of the patriarchal family, the validity of enslavement for unpaid debt, and the interference of religious custom in civil cases. That they reveal a remarkable liberality for their time with respect to testamentary rights and contracts is probably the result not of any innovations by the decemvirs but rather of the progress that had been made in commercial customs in Rome in an era of prosperity and vigorous trade.
Because only random quotations from the Twelve Tables are extant, knowledge about their contents is largely derived from references in later juridical writings. Venerated by the Romans as a prime legal source, the Twelve Tables were superseded by later changes in Roman law but were never formally abolished.