Stratford Langthorne Abbey, or the Abbey of St Mary's, Stratford Langthorne was a Cistercian monastery founded in 1135 at Stratford Langthorne — then Essex but now Stratford in the London Borough of Newham. The Abbey, also known as West Ham Abbey as it lay in that parish, was one of the largest Cistercian abbeys in England, possessing 1,500 acres (6.07 km²) of local land, controlling over 20 manors throughout Essex. The Abbey was self-sufficient for its needs and wealthy besides; some of this wealth came from the ecclesiastic mills grinding wheat for local bakers to supply bread to the City of London.