He returned a relic believed to be a part of St. Peter's staff to Archbishop Egbert of Trier in 980.
Otto was crowned King of Germany in Aachen on Christmas Day of that year by Archbishop Willigis of Mainz and Archbishop John of Ravenna, though custom dictated that Warin should have been in charge of the coronation as bishop of Cologne.
Though Otto died prior to his son's coronation, the news of his death did not arrive until after.
[2] Warin gave custody of Otto III to Henry the Quarrelsome, although modern sources disagree as to whether he did this willingly.
Modern scholars once again differ on whether Warin was supportive of Henry's attempt and to what extent.