Pope Adrian II (Latin: Adrianus PP. II, Italian: Adriano II; 792 – 14 December 872) was Pope from 14 December 867 to his death in 872. He was a member of a noble Roman family who became pope at an advanced age.
He maintained, but with less energy, the policies of his predecessor Nicholas I. Lothar II, king of Lotharingia, who died in 869, left Adrian to mediate between the Frankish kings with a view to assuring the Holy Roman Emperor Louis II the inheritance of Lothar II, Louis's brother. Adrian sought to maintain good relations with Louis, since the latters campaigns in southern Italy had the potential to free the papacy from the threat posed by the Muslims.
Photius, the Patriarch of Constantinople, shortly after the council in which he had pronounced sentence of deposition against Pope Nicholas I, was driven from the patriarchate by a new emperor, Basil the Macedonian, who favoured his rival Ignatius. An Ecumenical Council (Considered the 8th Ecumenical Council by the Catholic Church) was convoked as the Fourth Council of Constantinople to decide this matter. At this council Adrian was represented by legates who presided at the condemnation of Photius as a heretic, but did not succeed in coming to an understanding with Ignatius on the subject of jurisdiction over the Bulgarian church.
Like his predecessor Nicholas I, Adrian was forced to submit in temporal affairs to the interference of the emperor Louis II, who placed him under the surveillance of Arsenius, bishop of Orte, his confidential adviser, and Arsenius' nephew Anastasius, the librarian.
Adrian had in his youth married a woman named Stephania, by whom he had a daughter, and both were still living at his election, following which they lived with him in the Lateran Palace. They were carried off and assassinated by Anastasius' brother Eleutherius in 868.
Adrian died in 872 after exactly five years as pope.