After his wife, Elizabeth of York (-- not to be confused with Elizabeth Montgomery who played the wife of actor Dick York on "Bewitched") died the following year, rumor has it that Henry VII considered marrying the Spanish teen; but her Papa sent a NSFW missive across the miles squelching that ideas. That left only Henry Tudor, Arthur's little brother, as a viable option. The deal was sealed (literally, there were several seals on the betrothal document). The plan was for the marriage to take place when Henry turned 15 (June 28, 1506). In 1504, a papal dispensation was granted and there would have been great joy, except Isabella I died. Without Castile, Ferdinand II and his daughter fell several rungs down the social ladder. Henry VII decided that there were better potential wives for the younger Henry to consider. Henry's 15th, 16th, and 17th birthdays went by and still no wedding. Catherine remained stuck in England, with no option other than to wait for her fate to be decided.
Then, seven years after becoming a widow, Catherine was being fitted for a new wedding gown; one fit for a Queen. As luck would have it, Henry had recently ascended to the throne after tuberculosis claimed Henry VII's life. He agreed to honor his betrothal and marry the 23-year-old former Princess of Wales. A couple of weeks after the June wedding came the coronation ceremony. Before the month ended, Henry VIII celebrated his 18th birthday. June of 1509 was a busy month for the young king and queen.
I could tell you that their lives would only get better and the royal couple would live happily ever after. Unfortunately, in the 16th century, being royal was no fairy tale. I wonder if we'll see a happier Queen Catherine in the 21st.