Which sister of Edward IV married Charles the Bold of Burgundy?

Margaret of York was the sister of Edward IV who married Charles the Bold, Duke of Burgundy. She was a daughter of Richard, Duke of York, and Cecily Neville, and therefore a sister of both Edward IV and Richard III.

The marriage was arranged as a major diplomatic alliance between Yorkist England and Burgundy. Margaret and Charles married at Damme near Bruges on 3 July 1468, after lengthy negotiations and a papal dispensation because they were related within the prohibited degrees. She became Duchess of Burgundy rather than queen, since Charles never held a royal crown.

Margaret had no children with Charles, who died in 1477 at the Battle of Nancy. She then became an influential dowager duchess, supporting her stepdaughter Mary of Burgundy and encouraging Mary’s marriage to Maximilian of Austria. She is sometimes called Margaret of Burgundy, but Margaret of York is the clearest answer to this question.