Galen of Pergamum won the job of physician to the gladiators by slicing open a live ape and challenging senior doctors to repair it. This deep dive follows the audacious second-century physician who fused Greek philosophy, anatomy, and hands-on medicine into a system that dominated medical science for over 1,300 years.

We trace his path from a wealthy architect’s son sent into medicine by a dream of Asclepius, through his training in Alexandria, to Rome, where he humiliated rivals, fled assassination plots, and served the imperial family during the Antonine Plague. We also examine how a ban on human dissection led him to build theories on pigs and apes, and how his errors became untouchable medical dogma until Vesalius and William Harvey.

• Why Galen called gladiator wounds windows into the body, and how deaths dropped from 60 to five under his care
• The squealing pig experiment that showed the brain controls the voice
• His tripartite soul mapped onto the brain, heart, and liver, and an early form of talk therapy
• The one-way sprinkler model of blood flow and the invisible pores in the heart’s septum
• How Islamic and Christian scholars preserved his work and turned him into the medical pope