Altenburg was the seventh of nine children of Clemens Salvator, Prince of Altenburg, formerly Archduke of Austria-Tuscany, and his morganatic wife Elisabeth, , paternal grandson of Archduke Franz Salvator of Austria and his wife Archduchess Marie Valerie of Austria and maternal grandson of Friedrich Bernard, Graf Rességuier de Miremont, and wife Christiane, Gräfin von Wolkenstein-Trostburg.
