His life was chronicled by his contemporary Anselm of Liège.
[1] He is noted also for his nuanced approach to cases of heresy (not common in his day).
In a letter he wrote to Roger, Bishop of Châlons,[2] he quoted the New Testament Parable of the Tares and argued "the church should let dissent grow with orthodoxy until the Lord comes to separate and judge them".
[3] He was involved in the period 1021–5 in a controversy with John, canon and provost in Liège; Durandus of Liège, then bishop, had Wazo leave for a time.
[4] His election as bishop in 1041 was strongly contested,[5] with Emperor Henry III against him.