The former Breton and French diocese of Tréguier existed in Lower Brittany from about the sixth century, or later, to the French Revolution

French Revolution

The French Revolution , sometimes distinguished as the 'Great French Revolution' , was a period of radical social and political upheaval in France and Europe. The absolute monarchy that had ruled France for centuries collapsed in three years...

. Its see was at Tréguier

Tréguier

Tréguier is a port town in the Côtes-d'Armor department in Brittany in northwestern France. It is the capital of the province of Trégor.-Geography:Tréguier is located 36 m. N.W. of Saint-Brieuc by road. The port is situated about 5½ m...

, in the modern department of Côtes-d'Armor

Côtes-d'Armor

Côtes-d'Armor is a department in the north of Brittany, in northwestern France.-History:Côtes-du-Nord was one of the original 83 departments created during the French Revolution on 4 March 1790. It was created from part of the former province of Brittany. Its name was changed in 1990 to...

.

The title continues in the contemporary diocese of Saint-Brieuc and Tréguier.

History

St. Tudgual, nephew of St. Brieuc, was appointed by the latter at the close of the fifth century as superior of the monastery of Tréguier, which he had founded. The biography of St. Tudgual, composed after the middle of the ninth century, relates that King Childebert

Childebert

Childebert was the name of several Frankish kings:*Childebert I, king of Paris *Childebert II, king of Austrasia *Childebert the Adopted, king of Austrasia, known as Childebert III in France...

 had him consecrated Bishop of Tréguier; but Louis Duchesne

Louis Duchesne

Louis Marie Olivier Duchesne was a French priest, philologist, teacher and a critical historian of Christianity and Roman Catholic liturgy and institutions....

 argued that it was King Nomenoe who, in the middle of the ninth century, raised the monastery of Tréguier to the dignity of an episcopal see

Episcopal See

An episcopal see is, in the original sense, the official seat of a bishop. This seat, which is also referred to as the bishop's cathedra, is placed in the bishop's principal church, which is therefore called the bishop's cathedral...

.

Numerous synods were held at Tréguier in the fourteenth and fifteenth centuries, and passed regulations for the discipline of the Breton churches.

Bishops

• c. 1032: Wiliam I.
• c. 1045: Martin
• c. 1086: Hugo I. de Saint-Pabutral
• c. 1110–c. 1128: Raoul I.
• c. 1150–c. 1175: William II.
• 1175–1179: Ives I Hougnon
• 1179–c. 1220: Geoffroi I. Loiz
• c. 1224–c. 1237: Stephan
• c. 1238: Peter I.
• 1255–c. 1265: Hamon
• c. 1266–c. 1271: Alain I. de Lezardrieu
• c. 1284: Alain II. de Bruc
• 1286–c. 1310: Geoffroi II. de Tournemine
• c. 1317: Jean I. Rigaud
• c. 1324: Pierre II. de l'Isle
• 1327–1330: Ives II. Le Prévôt de Bois Boëssel
• 1330–1338: Alain III. de Haïloury
• 1339–c. 1345: Richard du Poirier
• c. 1354: Robert I. de Peynel
• 1355–1358: Hugues II. de Monstrelet
• 1358–1362: Alain IV.
• 28 November 1362–1371: Even Bégaignon
• 12 June 1372–1378: Jean II. Brun
• 1378–1383: Thibaud de Malestroit
• 1383–1384: Hugues III. de Keroulay
• 1385–3 May 1401: Pierre III. Morel
• 1401–1403: Ives III. Hirgouët
• 1404–1408: Bernard de Peyron
• 1408–1416: Christophe I. d'Hauterive
• 15. December 1417–1422: Matthieu du Kosker
• 29. April 1422–1430: Jean III. de Bruc
• 1430–27. August 1435: Pierre IV. Piédru (or Predou) (also Bishop of Saint-Malo)
• 1435–1441: Raoul II. Rolland
• 4. May 1442–1453: Jean IV. de Plouec
• 16. March 1454–23. September 1464: Jean V. de Coetquis
• 8. January 1466–1479: Christophe II. du Châtel
• 1480–1483: Cardinal Raphaël de Saint-Georges
  Raffaele Riario
  Raffaele Sansoni Galeoti Riario was an Italian Cardinal of the Renaissance, mainly known as the constructor of the Palazzo della Cancelleria and the one who invited Michelangelo to Rome. He was a patron of the arts...
  
  
• 1483–1502: Robert II. Guibé
• 1502–7. March 1505: Jean VI. de Talhouët
• 22 November 1505–16. November 1537: Antoine du Grignaux
• 14 June 1538–1540 or 1541: Louis de Bourbon-Vendôme
• 1541–1544: Cardinal Hippolyte d'Este
• 1544–1545: Jean VII. de Rieux
• 8 June 1545–1547: François I. de Manaz
• 1548–27. October 1566: Jean VIII. Juvénal des Ursins
• 1566–1572: Claude de Kernovenoy
• 1572–1583: Jean-Baptiste Le Gras
• 1583–1593: François II. de La Tour
• 1593–29. October 1602: Guillace III. du Halgoët
• 1604–29. July 1616: Georges-Louet-Adrien d'Amboise
• 1616–1620: Pierre V. Cornullier
• 1620–14. September 1635: Gui Champion
• 1636–19. August 1645: Noël des Landes'
• 1646–1679: Balthasar Grangier de Liverdis
• 1679–1686: François-Ignace de Baglion
• 1686–15. May 1694: Eustache Le Sénéchal de Carcado (or Kercado)
• 1694–1731: Olivier Jégou de Kervilio
• 1731–1745: François-Hyacinthe de La Fruglaye de Kervers
• 1746–30. August 1761: Charles-Gui Le Borgne de Kermorvan
• 1761–1766: Joseph-Dominique de Chaylus
• 26. April 1767–1773: Jean-Marc de Royère
• 1773–1775: Jean-Augustin de Frétat de Sarra
• 6 August 1775–1780: Jean-Baptiste-Joseph de Lubersac
• 1780–1790 (1801): Augustin-René-Louis Le Mintier