Several acts that a narrative may call an appointment must be distinguished. Election identifies a candidate through an authorized procedure. Canonical confirmation or institution supplies the title required by the relevant law. Episcopal consecration confers the sacramental order. A grant of property or regalia concerns temporal rights and obligations. These acts could be closely connected without becoming identical.
The controversy became acute because bishops were also important public figures. Rulers sought reliable officeholders, while reformers opposed simony and dependence that compromised ecclesiastical government. Ring and staff signified a bishop's spiritual office; their delivery by a ruler therefore carried implications that a grant of an estate alone did not carry.
At Worms in 1122 Henry V renounced investiture through ring and staff and recognized canonical election and free consecration. Calixtus II acknowledged specified imperial involvement and arrangements for the regalia. The agreement did not establish a modern religiously neutral state. It articulated a distinction within a Christian political society.
An irregular election, a corrupt transaction, a defect of canonical title and a question about sacramental validity are consequently not interchangeable charges. Each requires its own evidence and applicable principles. A historian who uses the single word appointment for all of them can miss both the reformers' central concern and the settlement's precise achievement.
The term is especially useful when reading accounts of Henry IV, Gregory VII, Paschal II and Henry V. It directs attention away from a contest of personalities alone and toward the institutional question: who may do what, by which authority, and with which effects?