Sestertius - Trajan S P Q R OPTIMO PRINCIPI S C, Pax

The legend OPTIMO PRINCIPI — "to the best ruler" — was not a standard imperial honorific but a title formally voted to Trajan by the Senate in 114 AD, though it appears on coinage somewhat earlier, reflecting the Senate's unusually warm relationship with an emperor who had pointedly reversed Domitian's autocratic precedents. The S P Q R framing was equally deliberate, casting the issue as a senatorial statement rather than imperial self-promotion.

RIC II 508 falls within Trajan's third coinage group, attributed to the period bracketing the Dacian Wars.