Calvisius Ruso was a governor of Britannia Inferior, a province of Roman Britain during the reign of Severus Alexander which was between 225 AD to 235 AD. It is unclear whether his governorship precedes or succeeds those of Valerius Crescens Fulvianus and Claudius Apellinus.
Epigraphic Evidence of Calvisius Ruso being Governor of Britannia Inferior
VOREDA (Old Penrith, Cumbria; RIB 929; dated: 225-238AD)
COH II GAL S A AMPLIAVIT …SVB CALVISIO RVSONE LEG AVG PR PR CVRANTE AVRELIO ”
[…] (this building) was made larger by the Second Cohort of Gauls, by approval […] under Calvisius Ruso, pro-praetorian legate of the emperor, in the administration of Aurelius”.