What if Arthur Tudor had become King?

Arthur Tudor has had a book written about him, which isn't a bad achievement considering he was dead by the age of 15. It considers why Arthur's memory was so deliberately forgotten during the latter Tudors' reigns, perhaps to avoid difficult suggestions about their own mortality and the precarious positions of their heirs. The article also indulges in a bit of virtual history - if Arthur had become King and remained happily married to Catherine of Aragon, would the English Reformation have taken place? Would Arthur have been able to give the Tudors the same strong identity as his brother? We will of course never know, but this exercise in counterfactual history is helpful in identifying which factors were crucial in shaping this period.

PS: Here is some more information about counterfactual history, including some academic links.