One thing I have pondered occasionally is the relationship between ways of abbreviating times and dates (e.g. 'on the 15th', or 'on March 1st') and usage. When you abbreviate the general assumption is that the most interesting information comes first and things that are less interesting - typically because they change less - are left to the end.

So to put it another way is the difference between American M/D/Y date order and European D/M/Y related to the sorts of dates people needed to talk about most?

I have no idea, to be honest, but it would be interesting to trace when the alternative orders became established and why.