Breguet’s most famous watch was the
“Marie-Antoinette” watch 

The watch was commissioned for Marie-Antoinette. Unfortunately, Marie-Antoinette never saw the watch as her head had been cut off 34 years before the watch was completed. She was 37 years old. 

The watch had every complication known at the time. Work on the watch started in 1783 and was finally completed in 1827, four years after Breguet's death.

The watch eventually ended up in the L.A. Mayer Institute in Jerusalem. It was stolen in 1983 and hasn’t been seen since.