The Messenger of Allah ﷺ freed Safiya bint Huyayy and made her freedom her dowry.
حدثنا هشيم عن عبد العزيز بن صهيب
أن رسول الله ﷺ أعتق صفية بنت حيي وجعل عتقها صداقها
Its isnad is sahih. Bukhari related it, 9/129, no. 5086, Fath, in the book of Nikah, chapter on making the manumission of a female slave her dower, and Muslim, 2/1045, no. 1365, and Abu Dawud, 2/221, no. 2054, and Tirmidhi, 3/414, no. 1115, who said, hasan sahih, and Nasai, 6/114, no. 3342, all of them in the book of Nikah, from Anas.