It's generally known that Henry Stafford, Duke of Buckingham, was arrested and executed in 1483 after joining the failed rebellion against Richard III, and it's often hypothesized that Harry was impelled to rebel in part because he was a closet Lancastrian. But did you know that in 1471, Harry was arrested--as a Yorkist sympathizer?
Harry, whose father had died in 1458 and whose grandfather the first duke had died in 1460, was a ward of the crown. He was first placed by Edward IV with Edward's sister the Duchess of Exeter; after the king's marriage to Elizabeth Woodville, Henry was transferred to the custody of Elizabeth, though the actual wardship remained in the king's hands. In 1465, Elizabeth was granted 500 marks per year for the maintenance of Harry and his younger brother. Woodville bashers like Annette Carson, who depicts Harry as being “kept at court tied to the queen’s skirts while she enjoyed the income from his estates,” have suggested that Elizabeth somehow deprived Harry of a normal knightly upbringing, but there's no evidence whatsoever of this. Elizabeth's household records are not extant after 1467 to give us any idea of how Harry was being raised; we know only that in 1466-67 he and his brother had a grammar master, John Giles, who was distinguished enough at his task to later teach Edward IV's own sons. We do know, however, that in 1470-71, probably after May 1471, Harry had a minstrel, who was traveling in company with the Duke of Gloucester's minstrel. The fact that Harry had his own minstrel at this time suggests that far from being deprived, Harry (who was born on September 4, 1455) had been given a household suitable in size for a teenage duke.
Harry's life took a turn in 1470 during Henry VI's brief restoration to power. He did not accompany Edward IV into exile or Elizabeth Woodville into sanctuary; instead, he was given into the custody of his grandmother Anne, the dowager Duchess of Buckingham, and her second husband, Walter Blount, Lord Mountjoy, who had to pay for his "support and finding," i.e., his expenses. On October 28, 1470, Harry went to supper with his paternal uncle Henry Stafford, who was married to Margaret Beaufort, Countess of Richmond. Margaret Beaufort's only son, Henry Tudor, was also visiting his mother and Henry Stafford during this time, so it's quite possible that Harry encountered the future Henry VII during this visit.
During Lent of 1471, Henry VI's government, or, to put it more accurately, the government of the Earl of Warwick, imprisoned suspected Yorkist sympathizers, housing some of them in the Tower. The list of arrestees included Harry's stepgrandfather, Walter Blount, his Bourchier relations, his uncle John Stafford, and "Lord Harry Buckingham"--that is, 15-year-old Harry himself. Harry is sometimes confused in the records with his uncle Henry Stafford, but Henry the uncle can safely be ruled out as the arrestee in this instance. Uncle Henry's movements during this time have been traced by Michael K. Jones and Malcolm Underwood, who note that he was being courted by the Lancastrians, through Margaret Beaufort's kinsman Edmund Beaufort, and chose at the very last moment to fight for Edward IV. Young Harry's own political sympathies during this time are unrecorded; as Hannes Kleineke notes, it appears that he was arrested simply because his guardian Walter Blount was.
The captives overpowered their guards on April 9 or 10, 1471, and escaped in time to meet Edward IV, who was returning from exile, and to accompany him to the battle of Barnet on April 14. What if any role Harry played in the Yorkist breakout and whether he accompanied the king to Barnet are, sadly, unrecorded, although we know that he was in the king's triumphant procession into London following the Yorkist victory at Tewkesbury. In the battles at Barnet and Tewkesbury that had preceded that procession, Harry's two Stafford uncles had fought for Edward IV; his two Beaufort uncles had fought (and died for) Henry VI. One wonders what young Harry, first in his prison cell and later in the king's entourage coming from Tewkesbury, thought about all of this.
Michael Hicks, False, Fleeting, Perjur'd Clarence: George, Duke of Clarence, 1449-78. Gloucester: Alan Sutton, 1980.
Michael K. Jones and Malcolm G. Underwood, The King’s Mother: Lady Margaret Beaufort, Countess of Richmond and Derby. Cambridge: Cambridge University Press, 1995.
Hannes Kleineke, “Gerhard von Wesel’s Newsletter from England, 17 April 1471.” The Ricardian, 2006.
Carole Rawcliffe, The Staffords, Earls of Stafford and Dukes of Buckingham 1394–1521. Cambridge: Cambridge University Press, 1978.