Adalbert I may refer to: Adalbert I, Margrave of Tuscany (c.820–886), guardian of Corsica Adalbert I of Ivrea, fl. c. 900 Adalbert I, Archbishop of Magdeburg (c. 910–981), Apostle of the Slavs Adalbert I, Count of Vermandois (915–987) Adalbert I von Saarbrücken (died 1137), Archbishop of Mainz Adalbert I, Duke of Teck (c. 1135 – c. 1195), German nobleman