"Order 66 was one of a series of contingency orders that the clone troopers of the Grand Army of the Republic were trained to prepare for during their growth. The order branded the Jedi as traitors of the Republic and called for their immediate execution without question. Its issuing by Supreme Chancellor Palpatine marked the formal beginning of the Great Jedi Purge, the rise of the Galactic Empire and was chief among the atrocities that led to the Galactic Civil War."
"The time has come. Execute Order 66." - Chancellor Palpatine to numerous clone commanders