The Synchronized Worlds are those planets under thinking machine domination and controlled by an incarnation of Omnius. By the time of the Great Purge, there were 543. During the Purge, they were nuked with atomics by the Army of the Jihad massive fleet until it converged on Corrin. The fleet was unable to proceed further and destroy Omnius Prime, resulting in a 20-year siege. The empty Synchronized Worlds were left far from the League of Nobles concerns, and were repopulated by cymeks.