Publius Juventius Celsus Titus Aufidius Hoenius Severianus (c. 67 – c. 130) — the son of a little-known jurist of the same name, hence also Celsus filius — was, together with Julian, the most influential ancient Roman jurist of the High Classical era.
Celsus was presumably born in upper Italy, where the gentilicium of Juventius was common and where senatorial Juventii can also be found.
In 114/115 he was governor of Thracia, and afterwards he became suffect consul for the nundinium of May to August 115 as the colleague of Lucius Julius Frugi.
He was part of the Consilium of Hadrian and helped bring about the Senatus consultum Iuventianum, which held that a good-faith possessor of an inheritance only had to yield it back inasmuch as he was enriched by it.
Another dictum of his, impossibilium nulla obligatio est – impossible obligations are void – has become a core tenet of civil law.