Messenger of Allah ﷺ manumitted Safiyya and then married her, and her Mahr was her manumission, and he gave a wedding banquet with Hais (a sort of sweet dish made from butter, cheese and dates). (Using translation from Bukhārī 5169)
أَنَّ النَّبِيَّ ﷺ «أَعْتَقَ صَفِيَّةَ وَتَزَوَّجَهَا وَجَعَلَ مَهْرَهَا عِتْقَهَا وَأَوْلَمَ عَلَيْهَا بِحَيْسٍ» خَالَفَهُ الزُّهْرِيُّ