The concept of promagistracy originally involved the notion of the promagistrate acting on behalf of a magistrate: pro consule (one behalf of the consul), pro preaetore (on behalf of the praetor).
Konsep promagistrasi awalnya melibatkan gagasan promagistrat yang bertindak atas nama seorang hakim: pro konsul (satu nama konsul), pro praetor (atas nama praetor).