When Pierre Garcie, a La Rochelle mariner (also called Ferrande), wrote his Grand routtier et pyllotage et encrage de la mer, he wrote that "piles of great stones" could be used as landmarks to enter the Morbihan Gulf: he was referring to the large Arzon and Locmariaquer tumuli.
The first explicit descriptions of the monuments only date back to the middle of the 18th century. These were due to marquis Christophe-Paul de ROBIEN, the well-read president of the Breton Parliament who happened to own Plessis-Caer Manor in the neighbouring parish of Crac'h.
One plate of his Histoire ancienne et naturelle de la province de Bretagne, clearly depicts "Mont Helleu" (Mané-Lud) clearly and Mané-er-Hroeg, Mané-Rutual, the Bronso menhir, the Table-des-Marchands and Grand-Menhir, as well as the Kergleverit dolmen, now in the neighbouring commune of Crac'h, can easily be recognised. All are in a state very similar to the one they were in when rediscovered by the early archaeologists, almost a century later.
The Mané-er-Hroeg tumulus and the two menhirs lying in front of it
The Mané-Rutual dolmen and its huge covering slab, next to the Bronso menhir, already fallen and broken in two.
The Table-des-Marchands dolmen and Grand-Menhir
The Table-des-Marchands was excavated as early as 1811.
The work was carried out by the Société armoricaine d'Auray (Auray Armorican Society) under the supervision of Mr. Renaud and was followed in 1813 by the excavation of Pierres-plates.
Both were described in an illustrated study published by A. Maudet de Penhouet in 1814.
The large Mané-Lud and Mané-er-Hroeg tumuli were excavated by the Société polymathique du Morbihan (the Morbihan archaeological society) in 1863-64.
It would be too long to list all the archaeological work that followed. However, the work carried out by Z. Le Rouzic should be noted. He explored the Er-Grah tumulus in 1908 and resumed earlier excavation and restoration work, in particular at Mané-Lud (1922 and 1930), Mané-er-Hroeg (1923), Mané-Rutual (1923 and 1936), Pierres-plates(1935-36) and more especially at the Table-des-Marchands (1921 and 1937). The latter excavation was to spark off a lot of controversy because of the way it challenged the traditional views of the monument.
Excavation of the Table-des-Marchands in 1811.