There are four effigies in the facade of Northumberland Street in Newcastle - Harry Hotspur, Roger Thornton, Thomas Bewick and Sir John Marley. In 1644, Sir John Marley, a staunch royalist, was the mayor of Newcastle. William Cavendish, Marquis of Newcastle was governor of the town, which had declared for the king in the English Civil War. At this time, the only northern town held by Parliamentary forces was Hull. Cromwell's alliance with the Scots altered matters and placed Newcastle in danger. On 3 February 1644, the Scottish army appeared before the town and demanded its surrender; this was refused. The Scottish commander, Leslie, who had been at the taking of Newcastle in 1640, was now the Earl of Leven. Rushworth tells us that an attack on the Shieldfield fort was driven off with loss, and the streets outside the walls set on fire by the garrison.
Leven now marched south to link up with the parliamentary general, Lord Fairfax. The marquis also left, to join the king at York. On 2 July the great battle of Marston Moor was fought and the royalists defeated. The marquis's whitecoats, enlisted from his own tenantry fought bravely but were cut to pieces and only thirty prisoners survived.
Leven resumed the siege of Newcastle and on 13 August the Scots, now reinforced, invested the town closely. Leven was quartered at Elswick, Callender at Gateshead. The latter established a battery below the Ouseburn, still known as Battery Quay. Headed by Marley 'unaided by superior military advice, the loyal ardour and unflinching courage of the townsmen enabled them to hold out against a numerous and well-appointed army, supported by the resources of two kingdoms.' According to Charleton, the attackers numbered 30,000, the garrison only 1500 men. Meanwhile, the bombardment caused many civilian casualties. The great Scottish traveller William Lithgow (1582-1645?) was present at the siege and has left a graphic and detailed account of Newcastle's walls, which he compares to those of Avignon, or Jerusalem in strength.
Leven now sent his famous threat to destroy the lantern tower of St Nicholas. Marley at once placed the Scottish prisoners there. He also sent a provocative letter to Leven which triggered a furious assault. Mines breached the walls in two places and the Scots forced their way into the town, suffering heavy losses. The Pilgrim Street Gate was taken in the rear, while Callender's brigade pushed forward to the Sandhill 'with colours flying and roaring drummes'. Only the castle keep remained to the garrison. It too fell after four days. Thus, after a siege of ten weeks, London's coal supply was guaranteed and parliament ordered a general thanksgiving. Marley was imprisoned, but to Lithgow's amazement, Leven permitted no pillage or slaughter. Sir John Marley, that brave and resourceful man, escaped abroad. In 1658 he is mentioned as having been seen in England on a secret mission regarding the restoration of the monarchy. He became mayor of Newcastle again in 1661 and died in his house there. King Charles I, in gratitude, had bestowed the motto the city bears to this day, Fortiter Defendit Triumphans.