In about 450 the number of tribunes was raised to 10.
Tribunes were required to be plebeians, and until 421 was the only office open to them. In the late Republic the patrician politician Clodius arranged for his adoption by a plebeian branch of his family, and successfully ran for the tribunate.
By extension from the technical Roman governmental usage, some modern politicians have been identified as "Tribunes of the People." {{the various Frenchmen who were proud of this title in the 19th century are escaping me!}}.