Colonne des Trente, Granite war memorial in Guillac, France

The Colonne des Trente is a granite obelisk at the lieu-dit La Pyramide in Guillac, Morbihan, beside the RN 24 expressway between Rennes and Lorient. Its shaft of stacked pale beige and off-white blocks tapers to a flat, angled top, and a square reddish-brown inscribed plaque sits near the bottom of the front face. It rises directly from the ground among dense trees.

The first stone was laid on 11 July 1819 and the granite obelisk was inaugurated on 6 July 1823 after four years of work. It honours the fighters of the Combat of the Thirty on 27 March 1351, a episode of the Breton succession crisis opened in 1341 by the death of Duke John III, though only the men of Charles de Blois's party are commemorated. It was inscribed as a monument historique on 15 May 1933.

The monument honours only the fighters of Charles de Blois's side; the opposing Anglo-Breton knights are not named. The 14th-century chronicler Froissart recounted the combat, which kept the episode alive in Breton memory. The site is known locally as La Pyramide, and the nearby motorway rest area carries the monument's name.

The memorial sits along Route D724 between two towns and is easily reached via this main road. The open access means visitors can stop by at any time to view the monument without advance notice or arrangements.

Before the obelisk was built in 1819, a stone cross from the 17th century marked the site of this historic battle. The cross was destroyed during the French Revolution, but the community rebuilt it before it was eventually replaced by the permanent granite monument.