Zonaras 7, 15.
number of the most prominent patricians actually did renounce their nobility, through desire for the immense influence possible, and so became tribunes.
Such was the origin of the power of the tribunes. In addition to them the people chose two aediles to be their assistants in the matter of documents. These took charge of everything that was submitted in writing to the plebs, to the populace, and to the senate, and kept it, so that nothing that was done escaped their notice. This and the trying of cases were the objects for which they were chosen anciently, but later they were charged, among other duties, with the supervision of the provision market, whence they came to be called agoranomoi [market-overseers] by the Greeks.
