Right now, international aid is normal enough that people would get pissed off if, say, the U.S. didn't send ships over to Haiti after a local catastrophe. It's almost seen as a responsibility. That's clearly a relatively new thing, but how new?
Follow up: what is the first example we have of nominally sovereign (or, for sake of ease, capable of waging mutual war and with separate governing bodies) entities rendering such aid? What about during times of hostility?