Appius Claudius Crassus Sabinus Regillensis, usually referred to simply as Appius Claudius Crassus or Crassinus, was one of the decemvirs, a committee of ten men chosen in the place of consuls to draw up the tables of Roman law beginning in 451 BC. He was the only member of the college to serve a second term in 450, having appointed himself to the position, together with nine others whose opinions agreed with his or whom he was able to dominate. They continued in office the following year, without bothering to hold elections, but were overthrown in a popular revolt, and the consular government restored.
Claudius is generally supposed to have been the son of Appius Claudius Sabinus Regillensis, consul in 471 BC, and grandson of the Appius Claudius Sabinus Regillensis who first migrated to Rome with his followers in 504 BC, and held the consulship in 495. The Gaius Claudius Sabinus Regillensis who was consul in 460 was his uncle. Claudius had at least two sons: the elder was Appius Claudius Crassus, consular tribune in BC 424; the younger was named Publius.
Some suppose the decemvir to be the same as the consul of 471, based on his filiation, Ap. f. M. n., in the consular fasti. Furthermore, both men were said to have killed themselves before they could be brought to trial for their misdeeds. However, chronology suggests that they were different people; the consul of 471 is supposed to have been a candidate for the consulship eleven years earlier, in 482, and his father was a wealthy and powerful man more than twenty years before that, which would have made the consul an older man at the time of the decemvirate, and when his son, the consular tribune of 424 BC, was born.
Both Livy and Dionysius describe the decemvir and the consul of 471 as different men, and refer to Gaius Claudius as his uncle. Moreover, the consul had already demonstrated his severity and enmity toward the plebeians, while the decemvir pretended friendship toward the common people, even appointing several plebeians as decemvir, until his true nature was revealed. Nonetheless, the identity of the two Claudii cannot be firmly rejected.