Answer
Emperor Charles V, the Holy Roman Emperor and King of Spain, employed Andreas Vesalius as his court physician. Vesalius, a prominent anatomist and author of the influential book "De Humani Corporis Fabrica," served in this role for several years, attending to the medical needs of the emperor and his court. During his tenure, Vesalius gained valuable practical experience in human anatomy, which contributed to his groundbreaking work in the field.