Celsus

Aulus Cornelius Celsus was a Roman encyclopaedist who wrote during the reign of Tiberius (14–37 AD). He compiled a vast encyclopaedia covering agriculture, military arts, rhetoric, philosophy, law, and medicine. Only the eight books on medicine, De Medicina, survive.

De Medicina is the most important Latin medical text before Galen. Written in elegant, lucid prose — Celsus was sometimes called the 'Cicero of medicine' — it covers dietetics, pharmacology, and surgery with remarkable clarity and practical detail. His account of the four cardinal signs of inflammation (rubor, tumor, calor, dolor — redness, swelling, heat, pain) remains one of the most famous passages in medical literature. His surgical chapters describe operations including cataract surgery, tonsillectomy, and lithotomy with a precision that suggests either extensive reading or personal observation in surgical theatres.

Whether Celsus was himself a practising physician is debated — he may have been a learned layman compiling expert knowledge. Either way, De Medicina preserves a comprehensive snapshot of Hellenistic medicine at its most sophisticated, much of which would otherwise be lost.