Degrees were first awarded as early as the 13th Century. At the time, the degrees were classified as "Scholar," "Bachelor," and "Masters." The Masters level was so named because it indicated the point at which a person was considered to have a mastery of the knowledge and information studied. In the 14th Century, people studying law and medicine where changed to the classification of "doctor." In the 16th Century, the classifications were further changed such that those areas previously deemed "Master of Arts" became the "Doctor of Philosophy" known today.
A doctoral degree generally qualifies the person who earns it to teach in that field in a college or university or to practice the profession for which they have earned the degree. It is quite often a requirement for employment in any of these areas.
While many doctoral degrees are Ph.D.s, there are many other doctoral degrees, most often in areas of professional rather than purely academic study, including medicine (M.D.), law (J.D.), divinity (D.D.), psychology (Psy.D.), and social work (DSW).
Doctoral degrees vary in the length of time needed for completion. In general, a degree can be earned in no fewer than three years. Quite often, earning the degree takes significantly longer. Most programs place specific time limits on their students to ensure they make appropriate and consistent progress on their degree.
People who earn a doctoral degree will receive a diploma indicating this just as with graduation from high school. In many cases, this diploma will be displayed in their office or practice which provides a means of verifying their successful completion of their studies and receipt of the corresponding credentials.