Adalbert I | |
|---|---|
| Archbishop of Mainz | |
 Sketch of the seal of Adalbert on a falsified document from 1174-1211 | |
| Church | Catholic Church |
| Diocese | Electorate of Mainz |
| In office | 1111–1137 |
| Predecessor | Ruthard |
| Successor | Adalbert II |
| Personal details | |
| Died | June 23, 1137 |
Adalbert I von Saarbrücken (died June 23, 1137) was Archbishop-Elector of Mainz from 1111 until his death. He played a key role in opposing Henry V, Holy Roman Emperor, during the Investiture Controversy, and secured the election of Lothair III rather than Henry V's chosen heir in 1125, causing later Holy Roman Emperors to make concessions in order to maintain hereditary monarchy.