Sir Humphrey Neville of Brancepeth (c.1439-1469) was member of the Lancastrian branch of the Neville family, and was one of the northern noblemen who refused to accept the Yorkist victory after the battle of Towton and continued to resist Edward IV until he was captured and executed in 1469.
The Neville family had their own internal feud that matched the wider split in the kingdom. Ralph Neville, first earl of Westmorland, had married twice. His title had gone to his oldest surviving son by his first wife (another Ralph Neville), but most of his lands went to Richard Neville, earl of Salisbury, his oldest son by his second wife.
Sir Humphrey was the first earl's great-grandson from his first wife (he was the son of Sir Thomas Neville of Slingsby, the third son of Sir John Neville, the eldest son of the first earl), and was thus part of the Lancastrian branch of the Nevilles. He was also a cousin of Richard Neville, earl of Warwick, and of John Neville, Lord Montagu, and although relations between the two branches of the family were often frosty there do appear to have been moments when Sir Humphrey worked for his Yorkist cousins.
Until the dramatic events of 1460-61 the Lancastrians were simply the supporters of the legitimate monarch, but after Edward IV's victory at Towton the Lancastrian cause never really recovered. Humphrey went into exile in Scotland, and in June 1461 we find him raiding into Durham in the company of Lord Ros. This raid ended disastrously for Humphrey, who was captured near Brancepeth, attainted by Parliament in November and imprisoned in the Tower of London. In February 1462 he was pardoned and granted his life, but only on the condition that he remained in prison. This clearly didn't appeal and he escaped in 1463 and returned to the north, where there was a small Lancastrian enclave based around the castles of Bamburgh, Alnwick and Dunstanburgh.
In June 1463 Neville came to terms with Edward IV (through the efforts of his cousin Lord Montagu), who was almost always willing to try and win over former Lancastrians. Neville was granted a pardon and even knighted by the king, but as was so often the case these efforts failed. By April 1464 Sir Humphrey had returned to his Lancastrian loyalties and was part of the garrison of Bamburgh Castle.
In the spring of 1464 Sir Humphrey's cousin Montagu was sent north to escort Scottish ambassadors to peace talks at York. Sir Humphrey attempted to ambush Montagu on the way, but failed. Henry Beaufort, duke of Somerset, was more successful in his attempts to intercept Montagu, but less successful on the battlefield and was defeated at Hedgley Moor (25 April 1464). Somerset regrouped his army, and then attempted to win a quick victory before Edward IV could arrive with the main royal army. This ended in the disastrous defeat at Hexham (15 May 1464). Sir Humphrey may have fought in this battle. He took part in the defence of Bamburgh, the only one of the northern castles to hold out for any length of time after Hexham. When Sir Ralph Grey, commander of the castle, was wounded, Sir Humphrey took over and negotiated a surrender in return for a pardon for himself and the garrison. Only Sir Ralph was excluded. After this Sir Humphrey fled into the wild border region between Durham and Northumberland, where he was able to remain in hiding until 1469.
In 1469 Warwick turned against Edward IV. He used northern revolts to successfully pull Edward out of position. Sir Humphrey probably took part in one of these uprisings, one of the few to end successfully. On 24 July 1469 Robin of Redesdale's men defeated Edward IV's allies at Edgcote (near Banbury), and soon afterwards the king was captured by Warwick's brother, George Neville archbishop of York.
If Sir Humphrey had taken part in one of Warwick's northern revolts it must have been because he expected it to lead to a Lancastrian restoration. When it became clear that Warwick intended to rule through either Edward or his brother George, duke of Clarence, Sir Humphrey began his own Lancastrian uprising in the north. Much to his dismay Warwick discovered that he couldn't raise troops to fight the rebels while Edward was being held prisoner and so he was forced to release the king.
Warwick was then able to raise troops and Sir Humphrey's revolt was quickly crushed. Sir Humphrey was captured, and on 29 September he was executed in front of Edward IV at York. The king used this opportunity to summon his allies to York and regain his independence, so Sir Humphrey's final efforts for the House of Lancaster ended up strengthening the position of the Yorkist monarch.