* Physical attraction. Catherine was reportedly very beautiful, and Henry was immediately smitten with her when they first met.
* Political alliances. Henry was eager to secure an alliance with the Howard family, who were one of the most powerful families in England at the time. By marrying Catherine, Henry could strengthen his position against his enemies.
* Lust. Henry was simply attracted to Catherine. She was young, beautiful, and seemed eager to please him.
Of course, Henry's marriage to Catherine was not without its problems. Catherine was accused of infidelity, and Henry eventually had her executed. However, for a time, she was the love of Henry's life.