The Messenger of Allah ﷺ freed Safiyyah and made her emancipation her dowry.
حدثنا قتيبة حدثنا أبو عوانة عن قتادة وعبد العزيز بن صهيب
أن رسول الله ﷺ أعتق صفية وجعل عتقها صداقها
Agreed upon [by Bukhari and Muslim]. Muslim narrated it in the Book of Marriage, in the chapter on the excellence of freeing one's slave-girl and then marrying her, hadith no. 1365, and in section 85 after hadith no. 1427, from Qutayba. Bukhari narrated it, hadith no. 5086, through another route, from the hadith of Anas, on the same subject, from Safiyya. [Tabarani in Al-Kabir, 3/24, 74, hadith no. 194].