'William de Ros, 4th Baron Ros of Hamlake' (
1325 –
1352) was a military commander under
Edward, the Black Prince. He was knighted by the Black Prince in
1346, having helped raise the
siege of Arguillon. In the same year, he was one of the lords who led the second division in the
Battle of Crécy, and afterwards commanded the fourth division of the English army against the Scots, near
Neville's Cross, when
David Bruce, with many of the Scottish nobles, was taken prisoner. In 1348, he was with the Black Prince, at the
siege of Calais, when it was taken by the English. In 1352, he accompanied
Henry of Grosmont, Duke of Lancaster, to fight the Saracens; but died the same year, before the feast of St Michael, aged twenty-six, on his journey to the Holy Land, and was buried abroad. He married Margaret, daughter of
Ralph, Lord Neville but died childless.