Anne of Cleves
Henry VIII got married six times.  Except for Anne of Cleves, Henry knew all of his wives for a long time before marrying them.  Henry decided to marry Anne so England and the Protestant League would be allies.  It was a political marriage.  Henry also knew that having more than one son would be good, in case his and Jane Seymour's son, Edward, died.  So he also married Anne so he could have more children.