Keeping Kings in Check 55
Th e Papacy
In the Roman Catholic papacy, the Eu ro pe an Middle Ages possessed some-
thing that the world would not see again until 1945: a transnational author-
ity whose legitimacy was widely recognized and which possessed certain
powers to infl ict various forms of punishment (or sanctions) onto rulers
who were in breach of their legal obligations. An early illustration of this
power at work occurred in the late fourth century, when Archbishop Am-
brose of Milan personally barred Roman Emperor Th eodosius I from enter-
ing the cathedral church of Milan because of a massacre committed by im-
perial troops for which Ambrose held the emperor responsible. Some of the
powers claimed by the popes were exercisable by the Catholic clergy gener-
ally. Th e most notable of these was the power to excommunicate named in-
dividuals— to cut them off from contact with other members of the faith
and to deprive them of their rights within the church.
Th e power of excommunication was exercised against a number of rulers
(and would- be rulers) in the course of the Middle Ages. In 1196, for exam-
ple, Pope Celestine III summarily excommunicated King Alfonso IX of
León for enlisting Muslim allies in an invasion of Castile. Pope Innocent III
(1198– 1216) made liberal use of this weapon. In 1209, he excommunicated
King John of En gland (in a dispute over candidates for archbishop of Can-
terbury). Th e following year, he did the same to Emperor Otto IV. Th is act
contributed to Otto’s replacement as emperor by Frederick II— who would
later himself be deposed by Innocent IV at Lyon in 1245. Long before that
event, in 1227, Frederick had been excommunicated by Pope Gregory IX for
excessive dilatoriness in embarking on a crusade to the Holy Land. In 1324,
Pope John XXII, playing an active role in a dispute over the emperorship,
excommunicated one of the claimants, Louis of Bavaria.
Ecclesiastical sanctions also included interdicts, in which church ser vices
could be withheld from an entire area. Th ese could be regarded as spiritual
counterparts of the later practice of economic sanctions. In 1141, Pope In-
nocent II, locked in a quarrel with King Louis VII of France (over a church
appointment), laid an interdict on any area that sheltered Louis. Th e same
fate befell the kingdom of León in 1197 at the hands of Pope Celestine III,
aft er King Alfonso IX’s marriage to a second cousin (contrary to church
law). In this area, too, the most active pope was Innocent III. He placed the