His father Robert Riddick Sr. was a lawyer who became collector of internal revenue during the American civil war, as well as clerk of Albemarle county and proctor of the university.

An opportunity to practice with A.C. Withers was accepted in 1880 and Prentis moved to Suffolk, which was his home for the rest of his life.

In 1927, Governor Harry F. Byrd, Sr. appointed Prentis the chair of a Commission to recommend Constitutional amendments to give cities and counties greater flexibility.

Its recommendations were based on the New York Bureau of Municipal Research and a Virginian Citizens' Committee on Consolidation and Simplification in State and Local Governments.

The latest, Robert Prentis Beaman III, followed in his namesake's footsteps, graduating from William and Mary Law School earning Order of the Coif honors, and currently resides in Portsmouth, Virginia.