The first legal text is the Law of the Twelve Tables, dating from the mid-fifth century BC. The plebeian tribune, C. Terentilius Arsa, proposed that the law should be written in order to prevent magistrates from applying the law arbitrarily. After eight years of political struggle, the plebeian social class convinced the patricians to send a delegation to Athens to copy the Laws of Solon; they also dispatched delegations to other Greek cities for a like reason. In 451 BC, according to the traditional story (as Livy tells it), ten Roman citizens were chosen to record the laws, known as the "decemviri legibus scribundis". While they were performing this task, they were given supreme political power ("imperium"), whereas the power of the magistrates was restricted. In 450 BC, the "decemviri" produced the laws on ten tablets ("tabulae"), but these laws were regarded as unsatisfactory by the plebeians. A second decemvirate is said to have added two further tablets in 449 BC. The new Law of the Twelve Tables was approved by the people's assembly.