In 1311 John de Warenne, 8th Earl of Surrey or Warenne was one of the nobles who captured Gaveston. The baronial opposition was led by the king's cousin Thomas, Earl of Lancaster, and he and Warenne became bitter enemies. Private war erupted between the two, and over the new few years Warenne lost a good part of his estates to Lancaster. Warenne was one of the four earls who captured the two Roger Mortimers, and in 1322 he was one of the nobles who condemned to death the earl of Lancaster. Warenne and his brother-in-law Edmund Fitzalan, 9th Earl of Arundel were the last two earls to remain loyal to Edward II after the rise to power of Queen Isabella and Roger Mortimer. After Arundel's execution he went over to the queen's side, urging Edward II's abdication in 1327. On May 25, 1306 Warenne married Jeanne of Bar, daughter of count Henry III of Bar and Eleanor, eldest daughter of king Edward I of England. The two were soon estranged and live apart, and had no children, though the marriage was never dissolved. Warenne instead took up with Matilda de Nerford, by whom he had several illegitimate children, and later with Isabella Holland, sister of Thomas Holand, later earl of Kent. Warenne died in 1347 and is buried at the monastery of Lewes. He was succeeded as earl by his nephew Richard Fitzalan, who was also earl of Arundel.

Ruins of Sandal Castle

The early history of Sandal Castle is first mentioned in a text from 1240, when it was likely that it was nearing completion. When the lands passed from royal ownership to William de Warrenne the second earl of Surrey between 1106 and 1121. William already had a base in Lewes Castle in Sussex which had been built by his father, and the Warenne family also built castles in Surrey (Reigate Castle) and near Doncaster (Conisbrough Castle). There was also a keep on the lands at Mortemer in Normandy. Sandal remained in this family's hands until the line lapsed with the death of John de Warrenne in 1347, at which the castle and the rest of the family's Yorkshire estates passed back to the king, Edward III.

The Wars of the Roses began the following year, with the first battle of St. Albans, fought on May 22, 1455 in the town St. Albans. The First Battle of St. Albans was trivial in military terms, with perhaps 300 dead, but the battle was a complete victory for York in political terms: he had captured the King, returning himself to complete power; his rival Somerset was dead; and the Neville's arch enemies Henry Percy, 2nd Earl of Northumberland and Lord de Clifford both fell during the rout. The Lancastrian army occupied the town but the Yorkist forces broke in and a battle took place in the streets of the town. On 17 February 1461 the Second Battle of St. Albans on Bernards Heath north of the town centre resulted in a Lancastrian victory where the Battle of Mortimer's Cross, led by Owen Tudor had been fought a few days before and surprised by the direction from which the Lancastrian's arrived from Dunstable rather than from Luton. Following the Reformation, St. Albans Abbey was dissolved in 1539 and the Abbey Church sold to the town.

Initially, Richard aimed only to purge his Lancastrian political opponents from positions of influence over the king. It was not until October 1460 that he claimed the throne for the House of York. In that yeare the Yorkists had captured the king at the battle of Northampton, but victory was shortlived. Richard and his second son Edmund were killed at the battle of Wakefield on December 30. York's defeat was probably the result of his own over-confidence, as he apparently refused to wait for reinforcements to arrive before leaving his stronghold at Sandal Castle to meet the Lancastrians, although it is also likely that the Duke was tricked by Lord Neville, riding under false colours, into thinking his force was greater than it actually was.

Early in 1460 the 3rd Duke of York, another Richard, made a bid for the throne himself. In December Richard went to Sandal Castle, either to consolidate his position or to counter some Lancastrian dissent. He had with him an army of 3,000-8,000 men, but on December 30 in the Battle of Wakefield he was outnumbered and outmanoeuvred by Queen Margaret's army, coming from nearby Pontefract. Richard suffered a crushing defeat and both he and his younger son Edmund, Earl of Rutland were killed (although only two months later Richard's eldest son Edward became king). The castle's last brush with royalty came in 1483 when Richard's eighth son (and twelfth child) Richard III chose it as a northern base and ordered some significant investments. This hope was short lived however as Richard was killed in the Battle of Bosworth in 1485. After this the castle was maintained a little, but gradually declined, with the building of Wakefield Prison in the 1590s leaving it even less useful.

During the English Civil War Sandal Castle was Royalist, although its neglected state left it out of the major conflicts. In 1645 however it was besieged at least three times by Parliamentarian troops. Having been assured that they would receive a safe passage to Welbeck House in north Nottinghamshire they surrendered the castle at 10 o'clock on October 1, 1645. The garrison was then 10 officers and 90 men with two of the men called "seniors" implying that they were professional soldiers rather than just non-commissioned officers. They also surrendered 100 muskets, 50 pikes, 20 halberds, 150 swords and two barrels of gunpowder: no pieces of artillery are mentioned. As a result of this capitulation only Bolton Castle in Wensleydale and Skipton Castle remained in Royalist hands in Yorkshire, but Sandal "was the most resolute of all the three northern garrisons" and its fall caused great rejoicing among the parliamentarian forces. By the end of this siege the castle was basically a ruin. The following yeare Parliament ordered that it be made untenable.

'The later middle ages: The Wars of the Roses', A History of the County of Yorkshire: the City of York (1961), pp. 59-61.