If you're looking for a historical accurate tale you should not watch this. There are more than "some events/persons that have been altered" for the story. The whole timeline of events is messed up. Meaning, many of those events happened at other times than shown here. This isn't a history lesson, it's a scripted drama. Entertainment. And that's totally fine with me because it does not claim to be anything else.
Historical drama is one of my guilty pleasures and this feels like watching something akin to Dallas or Denver in medival England. The costumes are amazing and having the oportunity of filming in this great locations is a luxury that makes this look so much better. The spanish accents are a little bit thick and sometimes it was hard to understand the actors. But in general they did a great job and I was especially taken in by Charlotte Hope.
Even from this mostly fictional depiction I gather that Catherine of Aragon must have been an interesting person and I might even take the time reading up about her. And if a show manages to do that I can only rate it as a success.