What would you take?

During a recent visit to a Roman site, Spot challenged me to come up with technology I would take to them, based on my knowledge and the ability they would have had to make the technology.

My initial thoughts were the steam train engine, but the blast furnace would be needed first, in order that the right grade of steal could be made. It would also need the development of the steam hammer, which needs a steam engine al a Watt. Spot did agree that all those were things the Romans probably could have made even if they hadn't.

But a bit later I thought on the bicycle. Just think how that could have improved communication throughout the Roman Empire, with all those great roads. They definitely could have made that, as they had good blacksmiths and the inventor of the bicycle, Kilpartick Macmillan, was one. As for tyres, rubber wasn't available to the Romans, but a suitably treated inflated intestine would probably do the job.

My other suggestion (and I must say, I thought that a bit of a stroke of genius) was movable type, a key element of the printing press as we know it (the Chinese, Japanese and Koreans had printing before Gutenberg, but they were wooden blocks which wore and could not easily be changed).

So, what would you take? I'm not too worried about changing world history here. I'm not The Doctor..