Alexandre, Chevalier de Vendôme

Alexandre de Vendôme (19 April 1598 – 28 February 1629) was the third illegitimate child, and second illegitimate son, of Henry IV of France and his mistress Gabrielle d'Estrées. He was a prior of the Langue of France of the Order of Saint John of Jerusalem.

Biography
Baptized in Saint-Germain-en-Laye on 13 December 1598, he was governor of Caen from birth throughout his life and entered the Order of Saint John of Jerusalem in 1604. King Louis XIII, his half-brother, appointed him to lead an embassy to Pope Paul V at Rome in October 1614.

In 1626 alongside his brother César, Duke of Vendôme and half-brother Gaston, Duke of Orléans, he participated in the conspiracy of Chalais, directed against Cardinal Richelieu, who was the Prime Minister of his half-brother, King Louis XIII. Arrested, he was incarcerated in Amboise, then in Vincennes where he died.