in feudalism, ceremony by which an overlord transferred a fief to a vassal or by which, in ecclesiastical law, an elected cleric received the pastoral ring and staff (the symbols of spiritual office) signifying the transfer of the office. After the oath of fealty, the lord “invested” the vassal with the fief, usually by giving him some symbol of the land or office transferred.
The dispute over clerical investiture was one of the great struggles between church and state in the Middle Ages. The problem stemmed from the dual position of the important bishops and abbots, who were temporal as well as spiritual lords. Thus from early times both king and pope were concerned with clerical election and installation.
When the struggle concerning investiture broke out (late 11th cent.), there was no general agreement as to the powers of the pope and the Holy Roman emperor in installing German bishops; it was only generally recognized that both had rights in the matter. Although investiture meant the ecclesiastical ceremony itself, it also more widely applied to the whole matter of election and installation. Lay investiture was the term used for investiture of clerics by the king or emperor, a layman. The right of a temporal prince to give spiritual power was claimed only by the extremists of the imperial party, but there was wide debate over canonical election, royal assent, and papal assent.
Pope Gregory VII and Holy Roman Emperor Henry IV began the open struggle. The clerical reform movement generated the crisis; it was essential that the church have the power of selecting bishops if church reforms—abolition of simony, clerical marriage, and political and economic abuse—were to be carried out. Holy Roman Emperor Henry III (d. 1056) had cooperated with the reform party, but in the minority of Henry IV, abuses were rife.
The reform party came to feel that complete abolition of lay investiture was the necessary prerequisite for its goals. In 1075, Gregory forbade lay investiture, and the bitter struggle began in earnest. The encouragement of rebellious nobles in Germany and the excommunication of Henry IV were followed by steady warfare. Although only one phase of the contest, investiture was a crucial issue. Especially in such difficult times, the emperor needed power over the bishop-princes. The papacy also maintained its ground.
After the death (1085) of Gregory VII, the argument took a new turn, and after the death (1106) of Henry IV the strain was lessened. However, Pope Paschal II, continuing the policy of his predecessors Gregory VII and Urban II, condemned lay investiture, although he entered negotiations for settlement. Holy Roman Emperor Henry V maintained the claims of his father and extended them ruthlessly. He made a vague settlement before his coronation, but at the last moment refused to surrender lay investiture; he seized the pope and forced him to surrender the church claims. Paschal later disavowed this forced agreement. The emperor and the antipopes he had set up effectively staved off settlement.
Under Pope Gelasius II some progress was made, but it was not until 1122 that churchmen succeeded in bringing about an agreement in the Concordat of Worms (see Worms, Concordat of) between Henry V and Pope Calixtus II. The compromise was a victory, although far from complete, for the church. The same problem recurred in struggles between the pope and other rulers. In France trouble between church and state centered in general on other issues (see Innocent III; Philip IV; Gallicanism).
In England, William I (William the Conqueror) came into conflict with the church, and William II embarked on a struggle over investiture. His abuse of power, particularly in keeping sees vacant, intensified the struggle that reached a climax in the long battle between King Henry I and Anselm. In 1107 a compromise provided that bishops and abbots should be invested by the church but should render homage to the king. Later trouble between church and state in England arose from other issues.