Sir Robert de Marny or Marney was an English knight who resided and died in Leyre-Marney, Essex.
In 1335 King Edward III accorded him confirmation of the de Marny family charter, dating back to 1266.
The date of marriage to Alice le Lacer is based on the death of her first husband, Sir William Bruyn d.1362, son of Maurice Bruyn according to his Inquisition Post Mortem.
The Manors included Rownor, Fordingbridge, Beckenham and Southwokyndon (Hampshire, Kent and Essex) De Marny fought in the Battle of Poitiers or Poictiers (1356) in which the English defeated the French.
He is best remembered now from William Morris's fictional poem "The Haystack in the Floods," which imagines his death in a skirmish while attempting to reach English-held Gascony.