SENATVS POPVLVSQVE ROMANVS
IMP CAESARI DIVI NERVAE F NERVAE
TRAIANO AVG GERM DACICO PONTIF
MAXIMO TRIB POT XVII IMP VI COS VI P P
AD DECLARANDVM QVANTAE ALTITVDINIS
MONS ET LOCVS TANTIS OPERIBVS SIT EGESTVS

Expanded:
Senatus populusque Romanus
Imperatori Caesari Divi Nervae Filio Nervae
Traiano Augusto Germanico Dacico Pontifici
Maximo tribunicia potestate XVII Imperatori VI Consuli VI Patri Patriae
ad declarandum quantae altitudinis
mons et locus tantis operibus sit egestus

The Senate and people of Rome
to the Emperor Caesar Nerva Trajan Augustus, son of Nerva of blessed memory
conqueror in Germany and Dacia, High Priest, vested with the tribunician power 17 times
proclaimed Imperator 6 times, elected consul 6 times, Father of the Country
as an illustration of the height which this hill and place attained,
now removed for such great works as these.