Hildesheim Diocesan Feud

The Hildesheim Diocesan Feud (German: Hildesheimer Stiftsfehde) or Great Diocesan Feud, sometimes referred to as a "chapter feud", was a conflict that broke out in 1519 between the Prince-Bishopric of Hildesheim (Hochstift Hildesheim) and the principalities of Brunswick-Wolfenbüttel and Calenberg which were ruled by the House of Welf. Originally just a local conflict between the Hildesheim prince-bishop John IV of Saxe-Lauenburg and his own prince-bishopric's nobility (Stiftsadel), it developed into a major dispute between various Lower Saxon territorial princes. The cause was the attempt by Prince-Bishop John to redeem the pledged estates and their tax revenue from the nobles in his temporalities, the prince-bishopric (Hochstift, or simply das Stift). The diocesan feud ended with the Treaty of Quedlinburg in 1523.

Due to his prince-bishopric's poor financial circumstances the Prince-Bishop of Hildesheim asked for the return of several estates pledged (or mortgaged) to the nobles within the prince-bishopric. As these estates were an important source of income, a small number of nobles and knights refused, however, to give up their mortgaged property to the prince-bishop. In parallel there were attempts by the House of Welf to redeem the land around Everstein pledged to the prince-bishopric which revealed differences between the Lüneburg line of the Welfs under Henry the Middle, the Welf lines in Brunswick-Wolfenbüttel, Calenberg and the Prince-Bishopric of Minden. To wit, in 1513, Henry the Middle received from Prince-Bishop John IV a large bill (Pfandsumme, i.e. pawned sum) for Everstein and thus set himself against the interests of the other Welf lines.

...
Wikipedia