This is a list of abbots of Monte Cassino.
Italian names are given in italics in parentheses for abbots before the third destruction of the abbey.
6th century
Benedict of Nursia (Benedetta da Norcia) : from 525/529
Constantine (Costantino) : 547–560? Simplicius (Simplicio) : 560?–576? Vitalis (Vitale) : 576?–580? Bonitus (Bonito) : 580?–584
Between and , the abbey was pillaged and burned by the Lombards and abandoned by its monks.
8th century
Petronax (Petronace) : 717?–747
Optatus (Optato) : 747? – 760
Ermeris (Ermeri) : 760–760
Gratian (Graziano) : 760–764
Tomichis (Tomichi) : 764–771
Poto (Potone) : 771–777
Theodemar (Teodemaro) : 777/778–796
Gisulf (Gisolfo or Gisulfo) : 796–817
9th century
Apollinaris (Apollinare) : 817–828
Deusdedit (Diodato) : 828–834
Hilderic (Ilderico) : 834–834
Autpert (Autperto) : 834–837
Bassacius (Bassacio) : 837–856
Bertharius (Bertario) : 856–883
In 883, the abbey was destroyed by the Aghlabids and the monks moved to Teano and later Capua.
Angelar I (Angelario) : 883–889
Ragembrand (Ragembrando) : 890–899
Leo (Leone or Leo) : 899–914
10th century
John I (Giovanni) : 914–934
Adelpert (Adelperto) : 934–943/944? Baldwin (Baldovino) : 943/944?–946 Maielpot (Maielpoto) : 943/944?–948
With Aligern, the monks return to Monte Cassino.
Aligern (Aligerno) : 948–985
Manso (Mansone) : 986–996
John II (Giovanni) : 996–997
John III (Giovanni) : 997–1010
11th century
John IV (Giovanni IV) : 1010–1011
Atenulf (Atenolfo) : 1011–1022
Theobald (Teobaldo) : 1022–1035
Basil (Basilio) : 1036–1038
Richer I (Richerio) : 1038–1055
Peter I (Pietro) : 1055–1057
Frederick (Federico) : 1057–1058
Desiderius or Daufer (Desiderio or Dauferio) : 1058–1087
Oderisius I (Oderisio) : 1087–1105
12th century
Otto (Ottone) : 1105–1107
Bruno (Bruno) : 1107–1111
Gerard (Gerardo) : 1111–1123
Oderisius II (Oderisio) : 1123–1126
Nicholas I (Nicola) : 1126–1127
Seniorectus (Senioretto) : 1127–1137
Rainald I (Rainaldo) : 1137
Wibald (Guibaldo or Wibaldo) : 1137
Rainald II (Rainaldo II) : 1137–1166
Theodin I (Teodino) : 1166–1167
Giles or Aegidius (Egidio) : 1168
Peter (Pietro) : 1168–1171 (apostolic administrator) Dominic (Domenico) : 1171–1174 Peter II (Pietro II) : 1174–1186 Roffred (Roffredo dell'Isola) : 1188–1210
13th century
Peter III (Pietro III) : 1210–1211
Adenulf of Caserta (Adenolfo) : 1211–1215
Stephen I (Stefano) : 1215–1227
Landulf Sinibald (Landolfo Sinibaldo) : 1227–1236
Pandulf (Pandolfo) : 1237–1238 (apostolic administrator) Stephen II (Stefano) : 1238–1248 Nicholas II (Nicola) : 1251 - ? Richard (Riccardo) : 1252–1262 Theodin II (Teodino II) : 1262–1263 Bernard Ayglerius (Bernardo Aiglerio) : 1263–1282 Thomas I (Tommaso) : 1285–1288 Ponce (Ponzio) : 1292–1292 William (Guglielmo) : 1293–1294? Angelar II (Angelario II) : 1294–1295 Berard (Beraudo) : 1295–1295 Bernard (Bernardo) : 1295–1296 (apostolic administrator) Galard (Galardo) : 1296–1301
14th century
Thomas II (Tommaso II) : 1304–? Marinus (Marino) : 1306–1313 Isnard de Pontevès (Isnardo) : ?–? : 1323–1326 (apostolic administrator)
From Raymond on, the abbots are bishops.
Raymond de Gramat (Raimondo) : 1326–1340
Guy of San Germano (Guido di San Germano) : 1340–1341
Richer II de Miremont (Richerio) : 1341–1343
(Stefano) : 1343–1345/1346
William II de Rosières (Guglielmo) : 1345–1346–1353
In 1349, the abbey was destroyed by an earthquake.
: 1353–1355
Angelo I Acciaioli : 1355–1357
Angelo II della Posta : 1357–1362
Angelo III Orsini : 1362–1365
Guglielmo III : 1366–1369
From Bartolomeo on, the abbots are once again monks (not bishops).
Bartolomeo da Siena : 1369–1369
Andrea I da Faenza : 1369–1373
Pietro IV de Tartaris : 1374–1395
Enrico Tomacelli : 1396–1413
15th century
Pirro Tomacelli : 1414–1442
Antonio Carafa : 1446–1454
From Ludovico on, the abbots are in commendam.
Ludovico Trevisan : 1454–1465
Pietro V Barbo : 1465–1471
Giovanni d'Aragona : 1471–1485
Giovanni de' Medici : 1486–1504
16th century
From Zaccaria on, the abbots are heads of the Cassinese congregation.