Marcus Calventius Viator was a soldier and commander of Roman Emperor

Roman Emperor

The Roman emperor was the ruler of the Roman State during the imperial period . The Romans had no single term for the office although at any given time, a given title was associated with the emperor...

 Hadrian

Hadrian

Hadrian , was Roman Emperor from 117 to 138. He is best known for building Hadrian's Wall, which marked the northern limit of Roman Britain. In Rome, he re-built the Pantheon and constructed the Temple of Venus and Roma. In addition to being emperor, Hadrian was a humanist and was philhellene in...

's horse guards, the equites singulares Augusti, during the early 2nd century.
Viator served as a centurion

Centurion

A centurion was a professional officer of the Roman army .Centurion may also refer to:-Military:* Centurion tank, British battle tank* HMS Centurion, name of several ships and a shore base of the British Royal Navy...

 in Legio IV Flavia Felix

Legio IV Flavia Felix

Legio quarta Flavia Felix , was a Roman legion levied by Vespasian in 70, from the ashes of the Legio IV Macedonica. The legion was active in Moesia Superior in the first half of the 4th century...

 and was training officer (exercitator) of Gaius Avidius Nigrinus

Gaius Avidius Nigrinus

Gaius Avidius Nigrinus 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...

' horse guards (equites singulares). He made a dedication at the legionary base in northern Dacia

Dacia

In ancient geography, especially in Roman sources, Dacia was the land inhabited by the Dacians or Getae as they were known by the Greeks—the branch of the Thracians north of the Haemus range...

 at Apulum

Apulum

Apulum may refer to:*The Latin name of Alba Iulia.*Apulum , the Roman fort of Alba Iulia.*Apulum , a Romanian porcelain manufacturing company....

 sometime between 110 and 118. In 118 Nigrinus was involved in a conspiracy with Lusius Quietus

Lusius Quietus

thumb|300px|Stylised Moorish Cavalry under Lusius Quietus, fighting against the Dacians. From the Column of Trajan.Lusius Quietus was a Roman general and governor of Iudaea in 117.- Life :...

against Hadrian. It has been speculated that Viator may have implicated Nigrinus, given his later promotion under Hadrian. Viator was promoted to the emperor's horse guards sometime before 128, being attested at Zarai in Africa Province.