The earliest versions of a doctoral degree originated in Europe during the Middle Ages as a license for a master to impart wisdom to students at the universities of that time. The meaning of the doctorate and the requirements to obtain one have evolved over time and differ considerably in different parts of the world. Today there are many different types of doctoral degrees, including research doctorates, higher doctorates (found in some countries such as the U.K. and Ireland), professional doctorates (Medical Doctor, Juris Doctor, Doctor of Business Administration, Doctor of Education, Doctor of Public Administration , and many others), and honorary doctorates. In most countries, including the U.S., the Doctor of Philosophy, or Ph.D., is generally the highest academic degree awarded in a field of study. The Ph.D. signifies that the student has not only mastered the body of knowledge in a particular field, but has also demonstrated the capacity to conduct original research and, in so doing, contribute to that body of knowledge. Though some other doctorates may have research components as part of the requirements, the Ph.D. is the doctorate regarded as a research degree.