Contrary to popular belief, the Hippocratic Oath (the Oath) is no fixed and unalterable document of medical ethics, but has been constantly modified over the centuries. Nor was it ever widely sworn or imposed as a condition for obtaining a degree or entering practice. The earliest certain evidence for the Oath taken in a university comes from 1558, and not until 1804 is there evidence for it being sworn by graduands or students. The demand for medical oaths and declarations is largely a feature of the second half of the twentieth century, favoured by physicians but often viewed with suspicion by patients.