The earliest doctoral degrees (theology, law, and medicine) reflected the historical separation of all university study into these three fields. Over time the D.D. has gradually become less common and studies outside theology, law, and medicine have become more common (such studies were then called “philosophy”, but are now classified as sciences and humanities – however this usage survives in the degree of Doctor of Philosophy).
The Ph.D. was originally a degree granted by a university to learned individuals who had achieved the approval of their peers and who had demonstrated a long and productive career in the field of philosophy (in the broad sense of the term, meaning the pursuit of knowledge). The appellation of “Doctor” (from Latin: teacher) was usually awarded only when the individual was in middle age. It indicated a life dedicated to learning, knowledge, and the spread of knowledge. The Ph.D. entered widespread use in the 19th century at Friedrich Wilhelm University in Berlin as a degree to be granted to someone who had undertaken original research in the sciences or humanities. Prior to the formal degree, the contemporary doctorate (PhD), arguably, arose in Leipzig as a successor to the Master’s (MA) degree in 1652 (Dr. habil).
Historically, lawyers in most European countries were addressed with the title of doctor, and countries outside Europe have generally followed the practice of the European country which had policy influence through modernization or colonialization. The first university degrees, starting with the law school of the University of Bologna (or glossators) in the 11th century, were law degrees and doctorates. Degrees in other fields were not granted until the 13th century, but the doctorate continued to be the only degree offered at many of the old universities up until the 20th century. As a result, in many of the southern European countries, including Portugal, Spain and Italy, lawyers have traditionally been addressed as “doctor,” (as well as Macau in China).
In some countries, holders of the first law degree traditionally use the title of doctor (for example, Peru, Brazil, Macau, Portugal, Argentina, and Italy).