n.
(Latin; " first one, " " leader ")
Unofficial title used by Roman emperors from Augustus (r. 27 BCAD 14) to Diocletian (r. 284305), a period called the principate.
The title originated during the Roman republic , when it was held by the leading member of the Senate. Its use by Augustus strengthened his claim to be the restorer of republican institutions and virtues, though he and his successors were in fact autocrats. See also prince .