Servant of the servants of God (Latin: servus servorum Dei[1]) is one of the titles of the pope and is used at the beginning of papal bulls.[2]
Pope St. Gregory I (pope from 590 to 604) was the first pope to use this title to refer to himself as Pope.[3] The adoption of the title stemmed from a dispute with the Archbishop of Constantinople John the Faster who adopted the title "Ecumenical Patriarch": the humble title "Servant of the Servants of God" countervailed the other's claim of power and eminence against the Bishop of Rome (the pope). Some of Pope Gregory's successors used the phrase off and on for some centuries, but they did so regularly only from the 9th century. At times, some civil rulers also used this title, but after the 12th century it came to be used exclusively by the Pope.
This papal title also has a biblical background found in the Gospel according to Saint Matthew, chapter 20, verses 25 to 27: