She was the second daughter of Henry of Milly or of Nablus, and first married William Dorel, Lord of Botron, having a daughter with him, Cécile.
After his death, she married Hugh III Embriaco, lord of Byblos (Gibelet) around 1179.
In 1197 she accompanied an army to besiege Byblos, which had been captured by the Muslims, and bribed a guard to open up the city to them.
With Hugo, Stephanie of Milly had two sons (Guido I Embriaco and Hugo) and two daughters (Plaisance, wife of Bohemond IV of Antioch and Pavie, wife of Garnier l'Aleman and mother of John Aleman).
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