actually burning down Rome didn't have any such major changes. There were other problems.
I actually think that we have to send a completely harmless book - how about hydro-electrial power plant sketches...
If we sent smthing like- "Brief history of Time" then a whole religion might form around it, but because that time people wouldn't understand it, they'll probably make smthing simmilar to christianity. And we'll hae another problem- besides it would lead their future scientists off course, because they would want nothing to do with that religion , but Hawking has some good ideas there and many scientifical facts. It would be bad if it is regarded as a fairy tale and if those scientists think that black holes is bs, then it would make some 100 more years to discover them.
a simple invention scheme I think would be the best
(please don't draw lines to christianity- I am talking only if it was Hawkings book, not some mythological legends)