Mellifont Abbey was the first Cistercian abbey to be built in Ireland. Founded in 1142 on the orders of Saint Malachy, Archbishop of Armagh, Mellifont Abbey sits on the banks of the River Mattock, some ten kms (6 miles) north-west of Drogheda. At its height, Mellifont was the mother house of 21 monasteries and as many as 400 monks made Mellifont Abbey their home.
After the Dissolution of the Monasteries under King Henry VIII, Mellifont Abbey was demolished and sold. A fortified Tudor manor house was built on the site in 1556 by Edward Moore, using materials scavenged from the monastic buildings. This house was the site of a turning point in Irish history. After Hugh O'Neill, last of the great Irish chieftains, was defeated in the Battle of Kinsale (1601), he was given shelter here by Sir Garret Moore. Mellifont was then the property of Garret Moore, 1st Viscount Moore, who was a close friend of the Earl of Tyrone. In 1603 the Treaty of Mellifont was agreed between the English Crown and Hugh O'Neill, Earl of Tyrone in the abbey grounds. It was Garret Moore who helped persuade O’Neill to sign the Treaty. O'Neill had surrendered to the English Lord Deputy Mountjoy and was pardoned, but he fled to the Continent in 1607 with other Irish leaders in the Flight of the Earls. William of Orange used Mellifont Abbey House as his headquarters during the Battle of the Boyne in 1690. The site of Mellifont Abbey and its manor house was abandoned in 1727.
Mellifont Abbey is now a ruin. The most significant remains of Mellifont Abbey are the chapter house, the Lavabo where the monks would have washed their hands before meals and the impressive gateway.