Porhoët

Both Guilliers and Porhoet are located in the modern day French departement of Morbihan in the province of Brittany.

It is still owned by the descendants of Porhoët and is the longest continuously held private estate in the world.

They had two children, Vicomte Geoffrey de Porhoët (1092–1141) and Alan I, Viscount of Rohan.

was next in line to the duchy (after Bertha); she married Alan, younger brother to Odo II, thus cementing Porhoët claims to Brittany.

When Bertha died, Odo II tried to deny Conan IV his inheritance and usurp the rule of Brittany.

He formed an alliance with Hoel, Count of Nantes, Conan III's disinherited son.

[b] In 1156 Odo was deposed by his step son and imprisoned by Conan IV's ally Raoul de Fougères.