Within its dominion, the diocese oversaw much of central Jutland, including the church's monasteries, friaries, and hospitals in that region.

The diocese comprised Viborg County, Aalborg, Slet, and the hundreds of Fleskum, Hornum, Hellum, Hindsted, Aars, and Gislum.

There were an additional Benedictine nunnery and a Franciscan friary in Aalborg which also fell under the dominion of the diocese.

His successor, Bishop Eskild, was similarly executed during Matins in the Church of St. Margaret, following an order from King Eric II.

[3] Bishop Niels I founded the hospital of St. Michael, Viborg, in 1159, and the Cistercian nunnery of Asmild in 1169.

He is largely responsible for the beatification of Saint Kjeld and the translation of his body to a shrine at his chapel on 11 July 1189.

It is believed that he is responsible for writing out the Law of Jutland and composing the original preface to it; he was present when it was published at Vordingborg in 1241.

His position in Viborg was succeeded by Canute Mikkelsen, who had been the dean of the Church of Our Lady in Copenhagen and rector of the University of Erfurt.

During his tenure, the lutheran preachings of Hans Tausen gained popularity in Viborg and threatened the bishop's authority.