In 1885, the historian Léon
Maître explains it in the "Bulletins d'archéologie de la Loire
Inférieure":
The map and documents register
of Redon (le Cartulaire) designates this parish by the name of
Grandis Campus, which should be translated by Grand Camp (Great
Camp) and not by Grandchamp, for two reasons:
- The environment aspect goes
against such a name;
- Important remnants of high
banks and deep trenches can be found.
Thus this name could be
justified by the presence of a reinforced camp.
A parish since 1790, it's only
in 1920 that Grandchamp is called "des Fontaines", to
distinguish from the town in the Morbihan.
The first dwelling of
Grandchamp was probably a gallo-roman villa located near the
Nagia (also known as Hocmard), unless that it was an inn on the
"Via publica in plebe Gramcamp"!
Grandis Campis appears for the
first time under Charlemagne, in the year 808 at the "
Cartulaire de Redon". That is nearly 1200 years ago…
Parish since the IXth century,
Grandchamp was crossed by the ancient Via publica, which goes
from Nantes (Condevicum, Namnètes capital city) to
Rennes.
The whole territory is quite
uneven. North and west show a plateau, formerly covered with
moors, cultivated since the middle of the 18th century and
called "The Desert". The view reaches up to ten leagues and the
terrain is suitable for the installation of a shelter or a
fort.
Near the village of the Grand'H
aie, we find remnants of defences called "The Big Trenches".
The best-preserved part forms a straight line that goes north
to south from the lake of Haut Fay in Héric to the village of
Chanay in Grandchamp: this road is nearly two kilometre
long.
"The Big Trenches" may have
been the scene of fights as there was a field called "Saracen's
Graveyard". In 1830, a round fortification with a diameter of
about 20 metres was still here. The name of Grand'Haie is an
indication: first feudal castles were surrounded by ditches so
called.