Barons and castellans · Duchy of Brittany · as at first light, 1 January 1200

La Guerche

A border lord astride the Breton-Angevin march, holding La Guerche of the duke and Pouancé of the count of Anjou: exactly the kind of man whose double homage matters in 1199.

He backed Arthur.

Who he is

Name
William II of La Guerche (Guillaume de La Guerche)
Title
Lord of La Guerche and Pouancé
Since
Not pinned
Born
Not pinned
Confidence
medium

Named among Arthur's backers in the French Wikipedia life of Arthur.

Overlord

The duke of Brittany for La Guerche; the count of Anjou (John) for Pouancé

What it holds

  • La Guerche and its castle
  • Martigné-Ferchaud
  • Pouancé in Anjou (held of the count of Anjou)

How it was acquired

Hereditary.

Allies and rivals

Arthur's party; Craon and the Angevin march barons.

How things stand that morning

Holds both; Pouancé is an Angevin fief in the hands of an Arthur partisan.

Wealth

March tolls, forest.

Military

Castles of La Guerche and Pouancé.

Threats

  • John's seneschal at Angers, for Pouancé

Places of note

  • La Guerche: Seat
  • Pouancé: Angevin fief

Where the sources disagree

Evidence: Name from a secondary list of Arthur's supporters.

On the map: Approximate.

Primary sources for Brittany

Chronicles, registers, sagas and inscriptions written in or near 1200 that cover this entry. Each has its own page with editions, translations and where to read it.

  • Chronicles of the Churches of Anjou (Saint-Aubin, Saint-Serge, Saint-Florent and others), Various (monks of Angers and the Loire) (11th to 13th centuries; the Saint-Aubin annals run to the 1220s). The Angevin houses' own annals of the succession crisis in their city: Arthur received at Angers in 1199 with Constance and the Breton and Angevin barons, John's counter-moves, the defection of William des Roches and the Angevin lords to John, and the peace of 1200 that left Arthur John's vassal. Read online
  • The Great Chronicle of Tours, Anonymous (a canon of Saint-Martin of Tours) (about 1227). The Loire valley's view of the Angevin succession. Read online
  • History of the Dukes of Normandy and the Kings of England, Anonymous of Bethune (a clerk in the household of Robert VII of Bethune) (about 1220). A Flemish lord's clerk writing twenty years on, with a soldier's interest in who fought whom. Read online
  • The Acts of Philip Augustus, with Delisle's Calendar, Various (the French royal chancery) (1179 to 1223). The king's own charters and treaties for the year: the peace of Peronne with Baldwin IX in January 1200, the treaty of Le Goulet with John on 22 May 1200, the marriage settlement for Louis and Blanche, the privilege for the scholars of Paris, grants to towns, abbeys and Norman lords, and the first acts of the king's new acquisitions in the Vexin, Evreux and Berry. Read online

Sources and studies

  1. Arthur Ier de Bretagne (Wikipédia)

Last revised 4 November 2026. Published 4 November 2026. Suggest a correction on the OMNIA Discord.