[2] Although the letters convey a genuine friendship between the two (VII.1 mentions Geminus' illness), the first one appears only in the latter books of Pliny's collection; Ronald Syme explains this may be due to the fact that he, like Quintus Corellius Rufus and Calestrius Tiro, were living in Rome at the same time.
[3] According to an inscription found at Patrae, the praenomen of Rosianus Geminus's father was "Sextus".
[4] A military diploma, dated 16 June 123, attests that Geminus was suffect consul with Publius Metilius Secundus that year.
Geminus was propraetorian governor of the public province of Achaea in 122/123;[7] an inscription found at Cirta attests that his son-in-law Publius Pactumeius Clemens was his legatus or assistant during his year governing Achaea, which also attests Clemens served as his assistant much later when Geminus was governor of Africa.
[9] Geminus' name also appears in a number of inscriptions listing the names of the patrons of Ostia, along with his son Titus Prifernius Paetus Rosianus Geminus, the suffect consul of 146.