In 1437, Duke John V of Brittany raised Briord to the rank of a seigneury of high justice, endowed with a three-post gallows. Martin de Rezay brought the estate into another dimension.
If one had to remember a single name among the medieval masters of Briord, it would surely be that of Martin de Rezay. It was under him that the land became a power.
In 1429, Martin de Rezay — probably the son of Sevestre — was registered at the reformation of the nobility. The document names him lord of Rezay, of Briord, of La Jarrière, of La Merlatière, of Saint-Fulgent and of yet other lands. It specifies that he resided "in the parish of Port-Saint-Père".
This last mention is crucial: Martin de Rezay lived at Briord. It was no longer a distant land in a portfolio of assets; it was his residence, the heart of his power.
In 1437, Martin de Rezay obtained from Duke John V of Brittany a decision of major import: the elevation of Briord into a seigneury of high justice, with the right of a "three-post gallows".
To understand what this meant, one must recall the hierarchy of seigneurial justices. Low justice judged only minor disputes. Middle justice dealt with offences. High justice, for its part, gave the lord the right of life and death: it could pronounce the capital sentence.
The three-post gallows was the visible symbol of this power. Raised on a height, visible from afar, it proclaimed to all that the master of Briord could hang.
For a rural seigneury of southern Brittany, this legal elevation was considerable. It placed Briord in a higher category, that of the great châtellenies. It conferred on its lord an authority that few possessed in the Pays de Retz.
Henceforth, Briord was no longer a land. It was a power.
Under Martin de Rezay, the seigneury entered its most richly documented medieval period. The deeds multiplied, the rights grew more precise, and the boundaries of the estate were drawn with a clarity that the preceding centuries had not allowed.
It was this inheritance — a seigneury of high justice, established and recognised — that his successors would take up, until Pierre Landais made of it a fortress.