Hippocrates was a Greek physician born around 460 BC on the island of Cos. He is considered the father of modern medicine. The Hippocratic Oath is believed to be the earliest expression of medical ethics and is still used today by physicians. The original oath called on Apollo and other gods as witnesses and included promises to teach medicine, help the sick, avoid harming patients, keep patient information private, and more. A modern version updated the language while keeping similar ethical principles of caring for patients and doing no harm. Breaking the oath was taken seriously in ancient times and could mean losing the right to practice medicine, while today it may result in malpractice penalties.