The title of First Lady is something special and dates back to Dolley Madison.
Thomas Jefferson was a widower when he held office, and James Madison was his Secretary of State. President Jefferson asked Dolley to assist him at official events, thus dubbing her his 'First Lady'. This training, of course, gave her ample preparation for the future.
When James Madison took office, he relied on Dolley to do the same. She set many precedents and also established tradition in the White House. Upon her death in 1849, President Zachary Taylor eulogized her as the nation's favorite First Lady.
From that point on, the title has been passed down through the ages.
The agency representing the First Lady series is: