Juliana of Liège (also called Juliana of Mount-Cornillon), (c. 1192 or 1193 – 5 April 1258) was a medieval Norbertine canoness regular and mystic in what is now Belgium. Traditional scholarly sources have long recognized her as the promoter of the Feast of Corpus Christi, first celebrated in Liège in 1246, and later adopted for the Catholic Church in 1264. More recent scholarship includes manuscript analysis of the initial version of the Office, as found in The Hague, National Library of the Netherlands (KB 70.E.4) and a close reading of her Latin vita, a critical edition of which was published in French by the Belgian scholar, Jean-Pierre Delville.