The 1570 bull Quo primum of Pope Pius V in a Roman Missal. Below the name of the pope Pius Episcopus (Pius Bishop) appears his title Servus servorum Dei. Not all papal documents begin in this way, but bulls do.
^Gabriel Adeleye, Kofi Acquah-Dadzie, Thomas J. Sienkewicz, World dictionary of foreign expressions: a resource for readers (1999) "Servus servorum Dei", p. 361.
^Ian Robinson The papal reform of the eleventh century p326 - 2004 "Gregory bishop, servant of the servants of God, to the archbishops, bishops , dukes, counts and the greater and lesser men in the kingdom of the Germans, greeting and apostolic blessing."