#Change the balance of power between Rome and Carthage.
Change the balance of power between Rome and Carthage.
If Carthage became the great imperial power instead of Rome you'd have the heart of the religion in a more equatorial region, removing the more northern requirement for a midwinter festival. You'd likely end up with a different festival appearing around the autumn harvest instead.
This may or may not completely change global culture for the next 2000 years. Destroying the rest of history is, as usual, left as an exercise for the reader.