Gaius Prastina Messalinus was a Roman senator, active during the reign of Antoninus Pius.
Nevertheless, the most common form of polyonymic names would lead one to suspect Messalinus was adopted by a member of the Ulpii, likely named "Gaius Ulpius Pacatus"; an alternative explanation is that "Gaius Ulpius Pacatus" may be his maternal grandfather.
A third item of interest is his cognomen "Messalinus", which suggests a connection to one branch of the gens Valeria.
[3] The second appointment was after his consulate, as governor of the imperial province of Lower Moesia, a post attested by a military diploma dated to between the years 145 and 157.
[4] Alföldy dismisses identifying Messalinus with the Pacatus who was governor of Gallia Lugdunensis at some point between the years 138 and 161.