Andybob

“Henry VII’s paternal grandfather, Owen Tudor, and Catharine of Valois, the widow of Henry V, fell in love and had three sons (Edmund, Jasper, and Owen); but the parents may never have married. This ambiguity invited the stigma of bastardy. Because the boys were the children of a former queen of England, those guarding the rights of the minor Henry VI such as Humphrey, Duke of Gloucester regarded the children as a threat and so branded them illegitimate. Still, King Henry VI countenanced Owen Tudor’s sons, making them royal half-brothers. Edmund Tudor — Henry VII’s father — in 1453 at age twenty-three became the Earl of Richmond. Concerning this recognition, Eric Simons speculates, “whether [King Henry VI] and his Council were now convinced that [the young men’s] parents had been truly married at their birth, or whether they considered it politically advisable to remove the stigma of bastardy from the royal half-brothers, cannot be said” (6). In 1459-60, an act of Parliament affirmed the legitimacy of Edmund, Jasper, and Owen Tudor, chiefly because of their father’s Lancastrian services during the Wars of the Roses (Simons 5-6). Nevertheless, the taint of bastardy continued to surround the births of certain progenitors of the founder of the Tudor monarchy — Henry VII.”

Maurice Hunt - “Shakespeare’s ‘Richard III’ and the problematics of Tudor Bastardy”

So Jasper is not a bastard and has an Act of Parliament to prove it.