File:HRE Dioceses Prince-Bishoprics, C. 1780.jpg
All the Catholic bishops of the HRE were prince-bishops (Fürstbischof) and possessed a Hochstift and a seat at the Imperial Diet, with the exception of the bishops of Chiemsee, Gurk, Lavant and Seckau — the so-called Eigenbistümer — who were subordinate to the Archbishop of Salzburg, as well as the bishops of Breslau, Vienna, and the other bishops whose See lay inside the Habsburg hereditary lands (Austria, Bohemia, Silesia, Austrian Netherlands). While those bishops called themselves prince-bishops, they did not have a Hochstift or a seat at the Imperial Diet. They were therefore bishops in charge only of a diocese. (J. Whaley, Germany and the Holy Roman Empire. Volume I, Oxford University Press, 2012, pp. 89–90)
The prince-bishop of Strassburg (Strasbourg) lost effective control of his Hochstift on the west bank of the Rhine when Alsace fell under French rule in 1648. However, two small territories on the east bank survived under his temporal rule and he therefore remained a prince-bishop not only in name but in fact as well.
Français : On ne doit pas confondre diocèse et évêché (évêché princier ou Hochstift en allemand) dans le cas du Saint-Empire Romain Germanique. Le diocèse était toujours plus vaste que le Hochstift qui, parfois, débordait sur le diocèse d'un autre évêque.