A discussion of some of the most important general characteristics of Trajan's imperial coinage, including an analysis of the much-used and highly recognizable reverse legend "SPQR OPTIMO PRINCIPI". The article goes back to a lecture delivered at a symposium jointly organised by the Association for Roman Archaeology and the Society for the Promotion of Roman Studies (the "Roman Society") at the British Museum on 16 December 2017 to mark theanniversary of the death of Trajan in AD 117.
Bernhard Woytek (Sun,) studied this question.