Hatfield Broad Oak Priory, or Hatfield Regis Priory, is a former Benedictine priory in Hatfield Broad Oak, Essex, England. Founded by 1139, it was dissolved in 1536 as part of Henry VIII's dissolution of the monasteries.
The large settlement of Hatfield was well established by the time of the Norman Conquest, and the Domesday Book lists the presence of a Saxon church. At one time a royal manor of Harold I, it fell into the possession of William I at the Norman Conquest. Popular for hunting in the neighbouring forest, the royal estate came to be known as Hatfield Regis (Latin for the king's Hatfield).
The Benedictine monastery itself was founded in or before 1139, one of the five religious communities of that order to be founded in Essex. The priory was a daughter house of the Breton monastery of St. Melanius in Rennes, and was dedicated to "God, St Mary, and St. Melanius Redonensis". It was thus considered an "alien priory" as it was subordinate to a monastery outside England.
In around 1230 a fire destroyed part of the priory church, for whose repairs Henry III granted ten oaks each from the forests of Hatfield and Wristle.
John Lydgate, the poet, was elected prior in 1423 but resigned the office a few years later to concentrate on his travels and writing.
A dispute over tithes from the royal manor of Hatfield granted to the Augustinian canons of St. Botolph, Colchester, by King Henry I continued for decades. A compromise was established by two clerical commissioners appointed by the pope in 1194, but the issue was not entirely resolved for several more years.