Gaius Avidius Nigrinus (died 118) was a Roman that lived between the 1st and 2nd centuries.
Nigrinus’ paternal and maternal ancestors were Romans of the highest political rank. He was the son of an elder Gaius Avidius Nigrinus by an unnamed mother, his brother was the consul Titus Avidius Quietus and his paternal uncle was the proconsul Tiberius Avidius Quietus. Nigrinus’ family were wealthy, distinguished and well connected politically from Faventia (modern Faenza, Italy) and he was born and raised in Faventia. Nigrinus and his family may have been related to the consul Gaius Petronius Pontius Nigrinus, who had served his consulship at the time that the Roman Emperor Tiberius had died in 37.
His family had strong links to Greece. The father of Nigrinus, had served at an unknown date during the reign of Roman Emperor Domitian (81-96) as Proconsul of Achaea, as well as his paternal uncle. His family was friends of Greek Historian Plutarch and Roman Senator Pliny the Younger. Plutarch dedicated a writing piece to the elder Nigrinus and Quietus entitled ‘On Brotherly Love’.
Nigrinus was a long outstanding friend of the Roman Emperor Trajan and his family. He served as Tribune in 105. Nigrinus served as Legatus of Achaea and probably participated in Trajan’s attempt to recognize and stabilize the administration of the financially troubled province. Nigrinus later became the Roman Governor of Greece.
In 110, Nigrinus served as suffect consul. During the year of his consulship, Trajan sent Nigrinus as a special official to Delphi, Greece as a member of an advisory council to assist the politician, later Greek historian Arrian in settling boundary disputes. This event is known in Delphi, as there are honorific inscriptions dedicated to Nigrinus in Greek and Latin in Delphi recording his tour of duty in Greece.
Nigrinus was a trusted lieutenant to Trajan. Trajan appointed him as a Roman Governor of the Dacia. Nigrinus commanded considerable political respect, was a leading military general and could have been seen as a probable heir of Trajan.
In 117, Trajan had died and was succeeded by his paternal second cousin Hadrian. In the summer of 118 Nigrinus, was one of four senators to be executed from orders from the Roman Senate because he was involved in a plot to overthrow Hadrian. Nigrinus was dismissed at Faventia. He was probably involved in the plot because of his differing position on Hadrian’s imperial policy and due to his long friendship, high standing with Trajan, Hadrian could have viewed Nigrinus as a potential threat as a heir as ruling emperor.
Nigrinus in his life married an unattested Roman noble woman called Ignota Plautia. He had at least one known child a daughter called Avidia Plautia. Plautia would marry Hadrian’s first adopted heir Lucius Aelius Verus Caesar. Nigrinus would become the maternal grandfather of the Roman Emperor Lucius Verus, prince Gaius Avidius Ceionius Commodus, princesses Ceionia Fabia and Ceionia Plautia.