Guy Louis Jules de Lasteyrie du Saillant, 5th Marquis de Lasteyrie du Saillant (3 October 1879 – 14 August 1944), of Ponthieu, was a member of the Lasteyrie du Saillant noble family of France. Early life Guy Louis Jules de Lasteyrie du Saillant was born on 3 October 1879 and from birth until his father's death in 1923, he was referred to as "Count" Guy de Lasteyrie as it was customary to refer to the eldest son of a marquis as "Count." He was the eldest son of Louis Pierre Gilbert de Lasteyrie du Saillant, 4th Marquis de Lasteyrie du Saillant (1849–1923) and the English Olivia Elizabeth Goodlake (1853–1916), who were second cousins. His younger brother was Louis de Lasteyrie du Saillant (who married Henriette Chodron de Courcel, a daughter of Baron Alphonse Chodron de Courcel). His family had a home in Paris and in the French countryside, known as Château de la Grange-Bléneau. Through his father's family, Guy was a great-great grandson of American Revolutionary War hero Gilbert du Motier, Marquis de Lafayette through his youngest daughter, Marie Antoinette Virginie du Motier, who married Louis de Lasteyrie, Marquis de Lasteyrie, and had four children. Their son, and Guy de Lasteyrie's grandfather, was Adrien Jules de Lasteyrie, who married Olivia de Rohan-Chabot (a daughter of the émigré Louis de Rohan, Vicomte de Chabot, and Lady Charlotte Fitzgerald). His paternal great-uncle was Ambassador Philippe de Rohan-Chabot. His maternal grandparents were Thomas Mills Goodlake, the High Sheriff of Berkshire, and Emilia Maria (née Baker) Goodlake (a daughter of Lt. Col. Sir Edward Baker, 1st Baronet and Lady Elizabeth FitzGerald).. His maternal uncle was Crimean War soldier Gerald Goodlake VC. Career During World War I, his wife volunteered with the Red Cross of France by driving an ambulance while he fought with his cavalry regiment at the Front. In 1923, he officially became the Marquis de Lasteyrie du Saillant after the death of his father. His third cousin was Charles de Lasteyrie. Personal life On December 19, 1912, Guy was married to sculptor Constance Whitney Warren at St Patrick's Cathedral in New York City. Constance, who shared his love of horses, was from a large and prominent American family. She was the only daughter of George Henry Warren II, a granddaughter of George Henry Warren, cousin of Robert Walton Goelet and Edith, Lady Queensborough, and niece of Whitney Warren and Lloyd Warren, prominent