. Guy Louis Jules de Lasteyrie du Saillant was born on 3 October 1879. From birth until his father died in 1923, he was referred to as "Count" Guy de Lasteyrie, as it was customary to address the eldest son of a marquis as "Count." His family had a home in Paris and in the French countryside, known as the
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==