That being said I do not know the (official) reasoning behind the nickname. But to me I would have never thought about it having something to do with being the earliest city.
To get back to the football question I think it is fine to have one on here. But I would have asked the name of the most famous club. Even people who dont follow football hear those names now and then (same as with popstars, even if you dont follow it you hear of them), but what are the terms are for different competitions and subdivision or whatever, someone that doesnt follow it wouldnt know. Beyond the term fifa and worldcup. Those you hear often enough
But maybe this trip to italy was the source of his pizza trauma, that initated all the other comments ;)
Weird/interesting/funny etc how pisa is the best guessed answer, even than the italian name for italy.