Deuteronomy 21:11-13

and you see among the captives a beautiful woman, and desire her and would take her for your wife, then you shall bring her home to your house, and she shall shave her head and trim her nails. She shall put off the clothes of her captivity, remain in your house, and mourn her father and her mother a full month; after that you may go in to her and be her husband, and she shall be your wife.