Sayyiduna Anas (may Allah be pleased with him) says that a slave-girl fell to the share of Dihyah, and it was said: "O Messenger of Allah! A beautiful slave-girl has fallen to the share of Dihyah." Anas (may Allah be pleased with him) says: The Messenger of Allah (peace and blessings be upon him) bought her in exchange for seven persons, then handed her over to Umm Sulaym (may Allah be pleased with her) to prepare her. The narrator says: I think he said that she observed her waiting period ('iddah) in her house, and she was Safiyyah (may Allah be pleased with her).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قسم الفيء والغنيمة / 12756