The original line of the Seton's devolved upon Sir Alexander the 3rd who married Christian Cheyne, is known for the conspicuous part which he took in the defence of his country against the invasion of the English as the Governor of the town of Berwick, besieged by Edward III of England in 1333.  He succeeded in sinking and destroying by fire a great part of the English fleet. The siege eventually converted into a blockade, and as the supplies began to fail and starvation was imminent, the Governor agreed to capitulate by a certain day, and gave hostages among whom was his son, Thomas.  However, before the appointed period, a body of Scottish soldiers marched into Northumberland, and Edward insisted that the town should be surrendered. The besieged refused, and Edward, enraged at this refusal caused Thomas Seton and his brother William (previously captured) - to be hanged before the gate of the town. Another son of Sir Alexander Seton fell in their country’s cause - during the the attack on the English fleet at Berwick, July, 1333, leaving only two sons remaining, Alexander and John. Sir John Seton, the younger son founded the Seton's of Parbroath, and the eldest surviving son, the 4th Sir Alexander Seton, married Margaret Murray, and later sought refuge from his sorrows and troubles in a hospital of the order of St. John of Jerusalem, his only child Margaret becoming heiress of the extensive estates. She married Alan de Wyntoun, a cadet of her own family, and this marriage led to a sanguinary contest between rival, and disappointed suitors, called ‘the Wyntoun’s war’ which according to Wyntoun, the chronicler, caused more than a hundred ploughs to be laid aside from labour. Alan de Wyntoun died in the Holy Land, and his eldest son, Sir William Seton, was created 1st Lord Seton by King Robert II.