Born in the 2nd arrondissement of Paris in 1898, Grat graduated from the Lycée Condorcet with a bachelor's degree in letters in 1917.[1][2] Upon his graduation, he enlisted to fight in the First World War and was awarded a Croix de guerre for valiant service.[1][3] After the war, he pursued a degree in law at the École Nationale des Chartes and was appointed a member of the French Academy in Rome in 1923.[1][3] Grat spent two years researching Latin texts in the Vatican and discovered several previously unknown works written by Tacitus.[1][2] After returning to France in 1925, he became a lecturer at the École pratique des hautes études and was appointed a professor of palaeography at Sorbonne University.[1] From 1931, he taught the history of the Middle Ages in Nancy.[1]
In 1936, Grat was an independent candidate in the legislative elections in the department of Mayenne.[1] His wife's family owned large amounts of land in the area, allowing him to become a political influence in the largely agriculture-focused region.[1] Facing outgoing Deputy Joseph Boüessé, Grat was elected Deputy with 50% of the vote.[1][3] Sitting in the Assembly with members of the conservative Republican Federation party, he was concerned with agriculture, labor policies, and foreign affairs.[1] He opposed the 1936 devaluation of the franc and also conducted a mission in the Levant while secretary of the Foreign Affairs Committee.[1][2] While a politician, Grat also founded the Institute for Research and History of Texts, which focuses on researching ancient and medieval manuscripts.[1][3]
During the Second World War, Grat re-enlisted in the army and served on the frontline, again being rewarded the Croix de Guerre for his service.[1][3] In early 1940, he presented his concerns about the army's lack of preparation for war in the National Assembly.[1] On 13 May, three days after the beginning of the German invasion of France, Grat was killed in action near Volmerange-les-Mines.[1][4] He was temporarily buried in Fontoy. Grat was the first Deputy killed during the Second World War.[3]
