Proctor is a person who takes charge of, or acts for, another.
Proctor of the University of Cambridge, aquatint by John Samuel Agar after Thomas Uwins, from History of the University of Cambridge (1815) by William Combe
1674 engraving of a Proctor in the University of Oxford. From Habitus Academicorum, by George Edwards
Doctors' Commons, also called the College of Civilians, was a society of lawyers practising civil law in London, namely ecclesiastical and admiralty law. Like the Inns of Court of the common lawyers,
Proctor
…to undertake the duties that were performed in common law courts by attorneys and in the courts of equity by solicitors. Proctors were attached to the Doctors' Commons, which performed a similar function for civil law or "civilian" advocates (the doctors) to that of the Inns of Court for barristers. Reforms in the…
Doctors' Commons in the early 19th century
The Prerogative Office, Doctors' Commons, in 1860
This plaque on the Faraday Building on the north side of Queen Victoria Street marks the site of the now demolished Doctors' Commons.