During the 1530s Henry VIII remarried twice, each time annulling his previous marriage. The English laws outlining the prohibited degrees of relationship for marriage were changed upon each marriage in the First and Second Succession Acts.1 These Acts were passed in Ireland by an Irish Parliament in 1536-37 and became part of the Irish Statute Book.2 However, the second Act regulating Henry VIII’s marriage to Queen Jane3 (Marriage Act (No. 2) 1537) was never published and was unknown to Irish law for centuries. The Act made its return onto the Irish statute book in 20074 greatly extending the class of relatives prohibited from marrying and potentially annulling many Irish marriages. This article traces the fate of the lost Act and analyses the consequences of its rediscovery both on Irish marriage law and the legitimacy of the Irish Statute book.