Chronology of the Papal-Imperial Conflict

870-962  Period of rampant papal corruption
1039-1056  Reign of Henry III, height of Holy Roman Empire
1044-1046 Three rival popes claims office after Pope Benedict IX sells the office, then recants.
1046   Henry III deposes the three popes and begins a papal reform movement
1049-1054 Pontificate of Leo IX; Leo begins serious reform of simony, the practice of selling church offices
1054 The Great Schism; Western Roman Church and Eastern Orthodox Church break, pronouncing anathemas on each other.
1056-1106 Reign of Henry IV, main opponent to papal claims of authority
1059  Papal Election Decree; pope now to be chosen by college of cardinals
1073-1085  Pontificate of Gregory VII
1075  Gregory VII proclaims his list of papal prerogatives, Dictatus Papae; he bans lay investiture
1076    Gregory VII excommunicates and deposes Henry IV; German nobles threaten to elect a new ruler.
1077   Henry IV forced to humble himself before Gregory VII at Canossa
1080  Second excommunication and deposition of Henry IV; Henry invades Italy
1088-1099  Pontificate of Urban II
1095 First Crusade
1106-1125  Reign of Henry V, less interested in maintaining imperial authority
1122  Concordat of Worms, recognized the right of the emperor to have symbolical territorial jurisdiction, but also stressed the separate authority of the papacy to make its own ecclesiastical appointments
1152-1190 Reign of Frederick I, Barbarossa; second wave of royal opposition to papal control; tries to regain imperial control of Lombardy.
1154-1159 Pontificate of Hadrian IV. Handrian acts as a chief opponent to Frederick I.
1155   Execution of Arnold of Brescia, spiritual leader of the patrene rebellion in Rome, which attempted to strip papacy of its political power and wealth.
1159-1181   Pontificate of Alexander III
1176   Lombards defeat Barbarossa at Legnano
1180  Barbarossa defeats Duke Henry the Lion of Saxony
1190-1197  Reign of Henry VI
1194  Henry VI becomes king of Sicily
1198-1216  Pontificate of Innocent III--height of papal power in the medieval period
1211-1250  Reign of Frederick II; declares a return to imperial doctrine of emperor as "God's vicar on earth."
1214   Philip Augustus defeats Otto of Brunswick at Bouvines
1215  Fourth Lateran Council begins the Inquisition, defines the doctrine of transubstantiation, and refines the process of the Mass.
1227-1241  Pontificate of Gregory IX--suspends Frederick II as emperor
1232 Gregory IX forced to flee before rebellion in city of Rome
1243-1254  Pontificate of Innocent IV
1245 First Council of Lyons--Innocent IV excommunicates Frederick II
1254-1273 Interregnum in Germany--no imperial ruler
1273-1291 Reign of Rudolph of Hapsburg, gives up imperial claims for recognition by papacy
1274 Second Council of Lyons--Gregory X attempts to heal the Great Schism with Eastern Orthodoxy; no lasting results.
1282-1302  War of Sicilian Vespers, Sicilian independence gained from Holy Roman Empire for a century
1291 Fall of Acre, Last Crusade ends
1294-1303  Pontificate of Boniface VIII
1302  Boniface VIII issues Unam Sanctam
1303 Boniface VIII humiliated at Anagni by agents of Philip IV
1305-1314 Pontificate of Clement V; papacy moves to Avignon
1303-1378 Babylonian Captivity of papacy at Avignon; papacy controlled by Capetian kings. 
1378-1417 Papal schism: Two lines of popes result--one in France, the other in Rome
1409 Council of Pisa--elects pope to rival first two lines; ends up creating three lines.
1414-1418 Council of Constance--deposes Benedict XII (Avignon) and John XXIII (Pisa), recognizes the Roman line, and elects Martin V as the new pope (1417).
1417-1431 Pontificate of Martin V
1431-1449 Council of Basel declared itself superior to the pope and worked to resolve various political issues. It eventually dissolves under pressure from Frederick III and Pope Martin V; end of the conciliar movement
1440-1493 Reign of Frederick III
1458-1464 Pontificate of Pius II
1464 Pius II's attempt at leading a crusade fails

"All manner of thing shall be well/ When the tongues of flame are in-folded/ Into the crowned knot of fire/ And the fire and the rose are one." -- T.S. Eliot, Little Gidding