Wyart was born in Bauchian, France on Oct. 13, 1839. He enlisted in the Franco-Belgian Battalion (Papal Zouaves) on Aug. 22, 1860 becoming one of the first to answer the call of Bl. Pius IX. During the battle of Castelfidardo on Sep. 18, 1860, he received a gunshot wound that broke his left forearm and a bayonet cut to his neck. He remained in the Battalion when it officially transitioned to the Papal Zouaves and was promoted to Sergeant on Mar. 21, 1861.

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Five years later on March 6, 1866, he was promoted to Sergeant Major then was quickly promoted to 2nd Lieutenant on March 17, 1866 and then 1st Lieutenant the following December. He distinguished himself during the Battle of Mentana on Nov. 3, 1867 and was promoted to Captain.

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During the fall of Rome on Sep. 20, 1870. He bravely defended the gate of Saint-Sébastien. After the fall of Rome he went with the French Papal Zouaves to fight against the Prussians during the Franco-Prussian war. He fought in the battles of Orleans, of Brou, and Loigny.

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He was promoted to Major shortly before the war ended in mid 1871. At the end of his military career, he was a member of the Legion of Honor, the Order of Pius IX, and the Order of Saint Gregory the Great, and received the Pro Preti Sede, Fidei et Virttuti, and Benemerenti Medals.

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On Feb. 5, 1872 he entered the Roformati Cistercian Order (Trappists). In 1877, Wyart was ordained a priest and took the name Sébastien in honor of the Saint whose namesake he defended during the battle of Rome at the Saint-Sébastien gate.

 

In 1880, he was elected Abbot of Mont des Cats. Then a few years later, Abbot of Septfonds and Vicar General of the Order. He founded several new abbeys, two in the Netherlands, one Rome, and one in Syria. In 1892 he helped Pope Leo XIII gather in Rome, the 51 Superiors of the 3 different Trappist observances where they voted to leave the Cistercian Order and form the 'Order of Reformed Cistercians of Our Lady of La Trappe', formalizing their identity and spirituality as a separate monastic community. The Superiors wanted the most humble among them to serve as the Abbot General, so they selected Fr. Sebastian Wyrat. He died in Rome years later on Aug. 18, 1904. His body rests in the cemetery of the Abbey of Three Fountains in Rome.