In December 1560, she married Edward Seymour, Earl of Hertford without Elizabeth I's permission. They planned to keep it a secret for a long time. However, Katherine became pregnant quickly and by July of the next year, she could not hold her secret any longer. She first tried to get help from Bess of Hardwick, but Bess screamed at Katherine and made her go away. Then she went to see Elizabeth's great favorite, Robert Dudley. He listened to Katherine but promised nothing. The next day he told Elizabeth everything. Elizabeth was angry with this and put both Edward and Katherine in prison. She gave birth to a son in the Tower of London. The child's name was Edward. 