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 Crecy, 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 26, on his journey to the Holy Land, and was buried abroad. He married Margaret, daughter of Ralph, Lord Neville but died childless.
| Preceded by: William de Ros |
Baron de Ros | Followed by: Thomas de Ros |