First night is a former and now-outlawed custom practised in Westeros for many thousands of years. Under this custom, any noble could claim the right to spend the first night of any couple of lesser rank's marriage with the bride. It is not clear when this custom originated or how many of the old kingdoms used to practise it. The custom was outlawed during the reign of Jaehaerys I Targaryen (48-103 AL) at the behest of his sister-wife Alysanne, who considered it barbaric and unfair. It has remained outlawed ever since.