My great-great-great-grandfather Nero was the first watchdog at the United States Mint.  On January 6, 1793, the Mint paid three dollars for him - a lot of money for a dog back when many people earned a dollar or less for a whole day's work.  Legend has it that this U.S. Treasury seal, from around 1800, shows Nero guarding the key to a Mint strongbox.  Nero actually patrolled the grounds around the building in Philadelphia every night with the night watchman.

Who's the dog on this old Treasury seal?  Some people believe it's the first Nero.