The Middle Ages saw several generations of the family take up arms against the French during the Hundred Years' War, primarily beside the noble Midland families of Beauchamp, Beaufort, and Talbot, and spanning at least 70 years of the conflict. The first recorded was Sir William de Grenlay, William Greneleye or Guillaume Greenlee (c.1372) of Edgbaston, Warwickshire, who, with his soldiers, fought alongside Thomas Beauchamp, 12th Earl of Warwick, and Sir John Neville, heir apparent to the Earl of Westmorland, but was slain at the first Siege of Harfleur in 1415, and posthumously commended by King Henry V. His kinsmen, John Grenlay, Grenley or Greneley (c.1417), was also at the siege under the command of Thomas Beaufort, Duke of Exeter, and subsequently garrisoned at Harfleur until it fell to the French in 1435, and Thomas de Grenlay, Greneley or Greynley (c.1424), fought at the Siege of Louviers in 1431 and afterwards became twice Vice Chancellor of Oxford University in 1436 and 1437.