Henry Fitzroy, Lucas Hornebolte, c 1534, watercolour and bodycolour on vellum, The Royal CollectionThe Tudors had a great problem with surviving sons. Henry VIII's older brother and heir to the throne, Arthur died as a teenager while another brother in childhood. Henry VIII himself saw two sons from Katharine of Aragon dying within weeks from their birth. Both Katharine of Aragon and Anne Boleyn had a series of miscarriages something that certainly contributed to their falls. By 1536 Henry was growing old (in Tudor England standards of course) and had no male heir (he had two daughters but at that time a woman was not considered a sensible choice for the throne). He had however an illegitimate son. Henry Fitzroy was born in 1519 and his mother was one of the king's mistresses, Elizabeth Blount. Henry VIII recognized him as his son and in due time gave him the title of 1st Duke of Richmond and Somerset. Was he intending to make him officially his heir in case he did not have any other male children? No one can provide an answer to this question as the boy died as a teenager like his uncle Arthur and his brother, the future Edward VI who was born almost a year after Fitzroy's death.
This is a lovely miniature portrait of the king's son by Lucas Hornebolt which was created approximately two years before the boy's death.
Picture from: http://tudorhistory.org/people/fitzroy/