[1] Prior to his appointment as archbishop, Werner was the provost of Maria ad Gradus, which Anno had founded in Cologne.
Adam of Bremen in his Gesta Hammaburgensis ecclesiae pontificum cites the case of Werner as exemplary of Anno's baleful nepotism.
The anonymous author of the Gesta archiepiscoporum Magdeburgensium [de] considered Werner to lack qualification for high office, being "a mild man and not sharp-witted".
[4][5] According to Bruno of Merseburg, his reasons were the same as those of the princes and boiled down to opposition to Henry IV's policy of recovering demesne lands in eastern Saxony that had been usurped during his minority.
[1] A letter addressed by Werner to Archbishop Siegfried I of Mainz in 1074 or 1075 is an important source on the early phase of the revolt and the rebels' thinking.
According to Werner, Henry IV seized the Saxon princes' lands arbitrarily and "not because of any fault on our part", but in order to reward the less wealthy members of his household (familiares), and then "fortified the more inaccessible places in our region with very strong castles."
[7] In the spring of 1075, according to Bruno, Henry IV was willing to reconcile with Werner and the other Saxon rebels on the condition that they hand over Burchard of Halberstadt and the other major conspirators.
[13] Werner is described as "a shadowy figure" compared to his "astute and energetic" nephew, although he had brought some benefit to his church from royal generosity during the first decade of his episcopate.