Aulus Cornelius Celsus (25 BC—50) was a Roman encyclopedist and possibly, although probably not, a physician. He probably lived in Gallia Narbonensis. His only extant work, the De Medicina, is the only surviving section of a much larger encyclopedia, and is a primary source on diet, pharmacy and surgery and related fields. The lost portions of his encyclopedia likely included volumes on agriculture, law, rhetoric, and military arts. Celsus' De Medicina is one of the best sources on Alexandrian medical knowledge.
In the "Prooemium" or introduction to "De Medicina" there is an early discussion of the relevance of theory to medical practice and the pros and cons of both animal experimentation and human experimentation.
Celsus is credited with recording the cardinal signs of inflammation: calor (warmth), dolor (pain), tumor (swelling) and rubor (redness and hyperaemia). He goes into great detail regarding the preparation of numerous ancient medicinal remedies including the preparation of opioids. In addition, he describes many 1st century Roman surgical procedures which included removal of a cataract, treatment for bladder stones, and the setting of fractures.
Celsus' work was rediscovered by Pope Nicholas V and published in 1478. His work became famous for its elegant Latin style.