According to Roman tradition, it was a Decemvirate (, 'decemvirs with consular power for writing laws') that drew up the Twelve Tables of Roman law.
Background
The setting up of the decemviri consulari imperio legibus scribundis occurred within the context of the two-hundred-year Conflict of the Orders between the patrician order (the aristocracy) and the plebeian order (the commoners). The patricians had developed into the upper class by monopolising the priesthoods, which played an important part in the politics of archaic Rome and, in the Early Republic, the consulship (the office of the two annual elected heads of the Roman Republic and the army), and the seats of the (unelected) senate, the advisory body for the consuls. They were also large landowners. The form of labour exploitation during this archaic period was the nexum, which was what historians call debt bondage, bonded labour, or debt slavery. The debtor pledged his labour services as collateral for debt. Defaulting debtors were liable to have their labour bonded for life.
In the early 5th century BC there was an increase in the problem of indebtedness due to the appropriation of public land (ager publicus) by the rich landowners to expand their estates (which restricted the amount of land available to small farmers), Rome's territory being attacked by neighbouring peoples and taxation. This also led to an increase in the problem of the abuse of defaulting debtors. Because of the absence of clearly defined laws and judicial procedures, the creditors could imprison and torture the debtors and, sometimes, sell them as slaves. This led to the First Plebeian Secession (494 BC), which was the start of the Conflict of the Orders.
The plebeians demanded that the state protect small farmers from the abuse of defaulting debtors by the creditors, who were the wealthy patrician landowners. When this was not forthcoming, they resorted to boycotting the military levy. At that time the Roman army was a part-time militia of peasant farmers who were drafted each year for the military campaigning season and then went back to their farms. Refusing the call-up gave plebeians significant political leverage. When their demands were not met, on their return from a defensive military campaign the soldiers refused to obey orders and seceded to Mons Sacer, outside Rome. They threatened to stay there until their demands were met. There were negotiations and the secession ended.
However, the plebeian demands were not fully met. Rather, they obtained the recognition of the institutions which they had created during the rebellion, the Plebeian Council (an assembly restricted to plebeians where they could debate their issues) and the plebeian tribunes. The latter acted as the defenders of the plebeians from abuse by consuls or officials through the provocatio, the power to veto the actions of the consuls and officials. They used it for actions they judged inequitable or abusive to any plebeian. They also convened and presided over the Plebeian Council and presented bills for its vote. An element of this conflict was about whether the resolutions of this council should be binding on all Roman citizens, including the patricians, or only on the plebeians. The plebeian institutions were parallel and separate from that of the Roman state (the consuls, the senate and the two other popular assemblies). Livy said "[t]wo states had been created out of one; each faction had its own magistrates [officials], its own laws." The main role of the plebeian institutions in the early days of the conflict of the orders was self-defence.