Why did Richard III’s army fail to support him at the Battle of Bosworth Field?

At the Battle of Bosworth Field, Richard III’s army did not fail to support him due to a single cause, but rather because of widespread desertion and the calculated betrayal of key nobles.

Richard’s position was severely undermined by his reputation, which had been damaged by rumors that he murdered his nephews and by his reliance on northern supporters, which alienated many in southern England. By the time of the battle, many of his supporters had deserted him.12

The most decisive factor was the conduct of the Stanley family. Thomas, Lord Stanley, and Henry Percy, earl of Northumberland, failed to assist the king despite being summoned. Thomas Stanley, who had married the mother of Henry Tudor, remained conspicuously neutral during the fighting. His brother, Sir William Stanley, had privately pledged support to Henry Tudor and intervened late in the battle by attacking Richard’s flank. This intervention caused the Yorkist army to collapse, leading to Richard’s defeat and death.341