Imperial abbeys (, also Reichsklöster and Reichsstifte) were religious houses within the Holy Roman Empire which for some period during their existence had the status of Reichsunmittelbarkeit ("imperial immediacy"): that is, such houses were answerable directly to the Emperor and were thus sovereign territories (however small), independent of other lordships. This status brought with it numerous other political and financial advantages, such as immunity from the authority of the local bishop, rights to demand various taxes and duties and to levy justice.

The head of an Imperial abbey was generally an Imperial abbot (Reichsabt) or Imperial abbess (Reichsäbtissin). (The head of a Reichspropstei - an Imperial provostry or priory - was generally a Reichspropst). Some of the greatest establishments had the rank of ecclesiastical principalities, and were headed by a Prince-Abbot or a Prince-Provost (Fürstabt, Fürstpropst), with status comparable to that of Prince-Bishops. Most however (and many of these religious houses had only very small territories) were Imperial prelates (Reichsprelaten) and as such participated in a single collective vote in the Reichstag as members of the Bench of Prelates, later (1575) divided into the Swabian College of Imperial Prelates and the Rhenish College of Imperial Prelates.

It was not uncommon for heads of religious houses other than the Imperial abbeys to have similar titles even though their establishments did not have Reichsunmittelbarkeit. To take three examples, the Prince-Bishop of St. Gall retained his title until the abbey was secularised in 1798, even though it had ceased to be an Imperial abbey in 1648; the abbot of Muri (which had a strong Habsburg connection) was created an Imperial prince in 1710, although by that time Muri was in Switzerland; and the Prince-Abbot of St. Blaise's Abbey in Baden-Württemberg held that title, not on account of the status of the abbey, which was not reichsunmmittelbar, but because it was conferred on him by the abbey's ownership of the County of Bonndorf.

Lists of Imperial abbeys

List A: Imperial abbeys named in the Matrikel

The religious houses listed here as List A are those named in the Matrikel, or lists of those eligible to vote in the Reichstag, including those whose votes were collective rather than individual. Three of these lists survive and are accessible, from 1521, 1755 (or thereabouts) and 1792.

This list includes the Principalities, Imperial abbeys (Reichsabteien and -klöster), Imperial colleges (Reichsstifte), Imperial provostries or priories (Reichspropsteien) and the single Imperial charterhouse (Reichskartause).

The word "Stift", meaning a collegiate foundation or canonry, possibly belonging to a variety of different orders or to none at all, and either with or without rules and vows, for either men ("Herrenstift") or for women ("Frauenstift"), has been left untranslated, except when it specifically refers to the chapter of a church.

Some of the imperial abbeys were dissolved during the Reformation; others were absorbed into other territories at various times in the general course of political life. Those in Alsace and Switzerland passed out of the Empire in 1648, when Alsace was ceded to France and Switzerland became independent. The great majority of these religious bodies however were secularised during the brief period that included the French Revolution, the Napoleonic Wars and their aftermath, especially as a result of the Reichsdeputationshauptschluss of February 1803. Any that survived, lost their Imperial titles when the Holy Roman Empire was wound up in 1806.

Abbreviations

• Dates column:

• * fdd stands for "founded"

• * RU stands for: "Reichsunmittelbarkeit granted".

• * Note: If no date is specified for the end of Reichsunmittelbarkeit, it is the same as the date of secularisation or mediatisation.

• Description and Imperial status column:

• * RA stands for Reichsabtei (Imperial abbey)

• * RF stands for "Reichsfürstentum" (Imperial Principality)

• * RP stands for "Reichspropstei" (Imperial provostry)

• College column:

• * RC stands for "Rhenish College"

• * SC stands for "Swabian College"

• * RF stands for "Reichsfürst", i.e., the head of the house in question had an individual vote; there were eight of these (counting Stablo and Malmedy as one).

List B: Reichsmatrikel 1521

The Matrikel of 1521 included a number of religious houses which have not been identified:

Inclusion in the 1521 Reichsmatrikel is not by itself conclusive evidence that a particular religious house was in fact an Imperial abbey, and the status of the following abbey listed in the Matrikel is questionable in the absence of further confirmation from other sources:

List C: Imperial abbeys not named in the Matrikel

For a variety of reasons a quantity of religious houses that possessed, or claimed, the status of Imperial immediacy either did not attend the Reichstag, or were not listed in the surviving Matrikel. The following list is very far from complete, and possibly some of those listed may not in fact have been reichsunmittelbar.