From everything I have seen so far about ethiopia, the only thing that made that Country survive that long and not being colonized was the fact that it was a Christian country.
For example: The help they recieved from Portugal in the Adal-Ethiopian war, or the help the recieved from Russia in the First Ithalo-Ethiopian war.
I'm sure there is a lot of factors that influenced Ethiopian history, but for me, the biggest deal was the Christianity.
So the question is what you guys think? I'm missing something to be more important? Is a very simplistic analysis?
Thanks :)
This older answer might be of interest to you.