There are no religious wars. All wars are fought for political reasons. Religion is just one of the wardrobe departments. The topic can do without sectarian turmoil.
The change from Julian to Gregorian happened at different times, not even counting the various conquests of regions with large non-Christian populations.
http://www.searchforancestors.com/utility/gregorian.html
Apologies, friend, if offense taken, but nothing in my post was inaccurate.