Noël Édouard, vicomte de Curières de Castelnau

Born in Aveyron to an Occitan family with a long history in their home province of Languedoc. His father was a lawyer who had once been the mayor of St. Affrique. Édouard was described as a broadly-built man of short stature, with dark hair and a tan complexion, and a perpetually serious look.[1] He joined the army in 1870 and fought in the Franco-Prussian War, 1870–71. He was Catholic and nicknamed le Capucin Botté (the fighting friar).

In 1900 he was removed from the General Staff for his anti-semitic, anti-Dreyfusard attitude. Nevertheless, Castelnau later became deputy to Joseph Joffre from 1911 to 1914, and helped develop the strategic Plan XVII for the recapture of Alsace-Lorraine as part of an invasion of Germany. In 1914 with war imminent, General de Castelnau was put in command of the French 2nd Army facing the oncoming Germans in Belgium. Under his leadership, in August 1914, the French 2nd Army was decisively routed by the Germans at the Battle of the Frontiers under Crown Prince Rupprecht of Bavaria, with the initial French 2nd Army offensive (along with the French 1st Army) being driven back by the Germans 25 km (16 mi) from the positions where the offensive had initially begun on 14 August. By the end of August, however, the French won back most of the territory lost in the hard-fought Battle of the Trouée de Charmes. The Battle of the Trouée de Charmes was a definitive victory for the Second Army; in stopping the Germans from passing through the Trouée de Charmes, de Castelnau possibly saved the French from disaster, but during this battle he lost his son Xavier, killed in action on August, 20th. Later, his two other sons Gerald and Hugues were to be killed in action in 1914 and 1915. The French were able to then organize a defense at Nancy and hold the city after victory in the Battle of Grand Couronné. It was suggested that this battle was decisive in the protection of Paris, by binding up significant German resources in static trench warfare for the duration in Lorraine.[2]

In June 1915 de Castelnau was appointed to command the newly created Central Army Group. Later that year he was made chief of staff to Joffre, and in 1916 he organised the initial defence at the Battle of Verdun, before appointing Philippe Pétain to the command.

After the dismissal of Joffre and the appointment of Robert Nivelle in 1916, Castelnau retired from active service. He was later sent on the Allied Mission to Russia in the early months of 1917, just prior to the Fall of the Tsar. When Nivelle was dismissed and replaced by Philippe Pétain, Castelnau was recalled to the command of the Eastern Army Group where he commanded the advance into Lorraine in 1918.

Three of Castelnau's sons were killed in the war. Recognizing the hopelessness of modern trench warfare, he once remarked: "Ah, Napoleon, Napoleon. If he were here now, he'd have thought of something else."[3]

After the war he entered politics. In 1919 he was elected to parliament as a deputy of Bloc National for Aveyron. In 1924 he founded the Fédération Nationale Catholique, which advanced a socio-religious model of France that has been described as "National Catholicism". In the same year Castelnau wrote an anti-Masonry pamphlet titled "La dictature de la maçonnerie en France" (The Dictatorship of the Masonry in France); he further publicized his accusations in a series of articles in Echo de Paris.[4] Although his Catholic Federation reached one million members in 1925, its significance was short-lived and it subsided into obscurity by 1930.[5]