For Rodulf Glaber, spiritual reform and material renewal were the rightful accompaniments to the millennial anniversaries of Christ's birth and passion. Reform encompassed material renewal, and relied as much on the mustering of popular indignation as on the work of legates and the promulgation of canons promoting free election and clerical chastity. The practice of the lay investiture of bishops and abbots, like simony and clerical marriage, had a long history in the Western Church. As his letters after 1075 show, Gregory VII increasingly began to see lay investiture as an unwarranted intrusion of laymen into ecclesiastical affairs. Although the issue would not finally be resolved until the Concordat of Worms in 1122, lay investiture became the contentious topic around which the reformers framed and waged their campaign for a freely established clergy especially after Gregory's death.