Sarah Whitney (March 22, 1825 - September 4, 1873) was only seventeen when her father, Newel K. Whitney, officiated her marriage to Joseph Smith. Newel, who was a close friend of Joseph, was even given a revelation (through Joseph, naturally) that this marriage was a wonderful idea - it would bring earthly blessings and seal the Whitney family's place in the Celestial Kingdom!
Let me emphasize this point: Newel and his wife Elizabeth secretly married their eldest (but still teenaged) daughter to a man 20 years her senior in exchange for a golden ticket to heaven.
People, if this sounds like a huge, manipulative con to you, let me say right now that there's nothing wrong with you. This arrangement looks shady and disgusting, and don't you doubt it!
It gets even shadier still. In mid-August Joseph, hiding from the law, tells Sarah and her parents that it is "the will of God that you should comfort me now" only to follow up with a warning to watch out for Emma, who, according Joseph, was dangerous. Joseph, on the other hand, was just a sick bastard (but at least he followed the divine mandate to marry a virgin).
The shadiness of this arrangement continues. Joseph then arranged a faux-marriage between Sarah and Joseph Kingsbury. I can only assume this was so it would be easier for Joseph to drop by on Sarah without creating suspicion. Very classy stuff. Very holy.
Joseph was killed less than two years later, at which point Sarah's marriage to Kingbury was disolved and Sarah went on to marry Heber Kimball, with whom she had seven children: David, David Orson, David Heber, Newel, Horace, Sarah, and Joshua. Her life ended in Utah before the age of 50.