Born in Vienna, Leopold was a younger son of Duke Albert II of Austria (thereby a grandson of King Albert I of Germany), and younger brother of the Dukes Rudolf IV and Albert III. His mother, Joanna of Pfirt, a daughter of Princess Joanna of Burgundy, was 51 when she gave birth to him and died shortly after. Upon the death of Albert II, his eldest son Rudolf IV, called the Founder, assumed the rule over the Habsburg dominions, despite the regulations on a joint rule left by his father. Nevertheless, on 18 November 1364 he promulgated his own house law ("Rudolfinische Hausordnung"), according to which the Austrian "hereditary lands" were again declared a common possession of the brothers, though the eldest received a number of additional rights.