On 24 Jun 1340 King Edward III of England (age 27) attacked the French fleet at anchor during the Battle of Sluys capturing more than 200 ships, killing around 18000 French. The English force included John Beauchamp 1st Baron Beauchamp Warwick (age 24), William Bohun 1st Earl of Northampton (age 30), Henry Scrope 1st Baron Scrope Masham (age 27), William Latimer 4th Baron Latimer of Corby (age 10), John Lisle 2nd Baron Lisle (age 22), Ralph Stafford 1st Earl Stafford (age 38), Henry of Grosmont 1st Duke Lancaster (age 30), Walter Manny 1st Baron Manny (age 30), Hugh Despencer 1st Baron Despencer (age 32) and Richard Pembridge (age 20).

Thomas Monthermer 2nd Baron Monthermer (age 38) died from wounds. His daughter Margaret Monthermer Baroness Montagu 3rd Baroness Monthermer succeeded 3rd Baroness Monthermer.