| YEAR | DATE | EVENT | HEAD OF STATE | |
| 1221 | Bishopland | Bishop Konrad II von Riefenberg | ||
| 1247 | Bishop Heinrich I von Wernigerode | |||
| 1257 | Bishop Johann I von Brakel | |||
| 1260 | Bishop Otto I of Brunswick-Lüneburg | |||
| 1279 | Bishop Siegfried II von Querfurt | |||
| 1310 | bishop Heinrich II von Woldenberg | |||
| 1318 | bishop Otto II von Woldenberg | |||
| 1331 | bishop Heinrich III of Brunswick-Lüneburg | |||
| 1363 | bishop Johann II Schladland | |||
| 1365 | bishop Gerhard von Berg | |||
| 1398 | bishop Johann III von Hoya | |||
| 1424 | bishop Magnus of Saxe-Lauenburg | |||
| 1452 | bishop Bernhard III of Brunswick-Lüneburg | |||
| 1458 | bishop Ernst I von Schauenburg | |||
| 1471 | bishop Henning von Haus | |||
| 1481 | bishop Berthold II von Landsberg | |||
| 1503 | bishop Erich II of Saxe-Lauenburg | |||
| 1504 | bishop Johann IV of Saxe-Lauenburg | |||
| 1527 | bishop Balthasar Merklin | |||
| 1531 | bishop Otto III von Schauenburg | |||
| 1537 | bishop Valentin von Teuteben | |||
| 1551 | bishop Friderik of Denmark | |||
| 1557 | bishop Burkhard von Oberg | |||
| 1573 | bishop Ernest II of Wittelbasch p.e. of Koln | |||
| 1612 | bishop Ferdinand of Wittelbasch p.e. of Koln | |||
| 1650 | bishop Maximilian Henry of Bavaria p.e. of Koln | |||
| 1688 | 7 jult | bishop Jobst Edmund von Brabeck | ||
| 1714 | 31 december | bishop Joseph Clemens Herzog von Bayern p.e. of Koln | ||
| 1724 | 8 february | bishop Clemens August I von Bayern p.e. of Koln | ||
| 1761 | 6 february | vacant | ||
| 1763 | 7 february | bishop Friedrich Wilhelm von Westfalen | ||
| 1789 | 6 january | bishop Franz Egon von Fürstenberg | ||
| 1802 | 30 july | Union to Principality Electoral of Brandenburg | ||
| 1918 | 7 november | Union to German State of Lower Saxony |