Dionisio Daza Chacón (1503–1596) was a leading Spanish Renaissance surgeon. He served under emperors Charles V and Philip II, gaining much of his expertise as a military surgeon on European battlefields. His career included campaigns in Flanders, Germany, Portugal, and the Mediterranean, where he accompanied Don Juan de Austria and fought at the “Battle of Lepanto. Daza Chacón worked in the same period of time with physicians like Andreas Vesalius and treated important figures such as Prince Don Carlos and possibly Miguel de Cervantes. His main work, Práctica y Teórica de Cirugía (1580), introduced modern methods for treating wounds, amputations, and cranial injuries. He worked at the same time but in the opposite French army with the famous surgeon Ambroise Paré. He rejected medieval beliefs such as the value of “laudable pus” and introduced modern wound classification and treatments. His innovations included vessel ligatures, new methods for amputations, and pioneering approaches to cranial surgery, leaving a lasting legacy in the history of medicine.