Galen came to anatomy through the wounds of the arena, serving as surgeon to the gladiators of Pergamon before rising to attend emperors at Rome. From the dissection of apes and pigs he built a vast and confident system of the body's workings.
His authority became so complete that for some fourteen hundred years to question Galen was to question medicine itself — until a man named Vesalius returned to the corpse and found the master had erred.