What should a time traveler introduce to modernise Rome as fast as possible?

Electricity, the lightbulb, the electric motor and generator. Then prepare to be burned at the stake for sorcery.

Sustainability.

Back then there was a bit more time before we screwed over humanity.

(The planet will be fine long after we've made ourselves extinct)

Easy to learn and fast to apply math notation across the board. Feel me?

public health, public education, representative democracy, universities

Sure, there's lotsa flashier tech; I'd start with the boring stuff above first

1. An old-fashioned paper encyclopedia set published no later than the birth of the atomic age. Something like the Encyclopedia Britannica, but with nothing that would lead to nuclear fission/fusion too quickly. Maybe the 11th edition? This has all the basic information for rebuilding a late 19th C culture, along with historical narrative. Include one of those old-fashioned paper historical overview timelines…for technology at least. Highlight all the important stuff to speed things up. Maybe rip out all the specific historical biographies to save space. Replace with a complete Bible and Koran…they already have a Torah.

2. If going the Britannica route, a very complete English/Latin dictionary.

3. K-12 physical toy demonstrations of electric generation and transmission, steam power, incandescent light, batteries, optics, telegraphy, photovoltaics, speakers/microphones. Basically a really really good science kit.

4. A historical atlas from the late 1800s of world mineral resources and mines, basically sans uranium.

5. Physical samples of modern steel, aluminum, coal, crude oil and various distillates, early plastics, optical glass, gunpowder, TNT, penicillin, sulfa drugs, streptomycin, morphine, ether, carbolic acid. Early papers on how to discover/manufacture these items, if the encyclopedia doesn’t cover in depth.

6. Three different modern varieties each of maize, potatoes, soybeans, wheat, canola, rice and apples, either seeds or cuttings. Chosen for varying cold and drought hardiness and productivity. Enough to sample as food and reproduce for a crop.

7. Small samples of “magical” technology. Mechanical watch. Solar calculator. 20th Century pistol, rifle and ammunition. Train set. Laser pointer. Model propeller airplane. Mechanical micrometer. Transparent model of internal combustion engine…the old V-8 model kits. Tiny movable type press kit. Harmonica, melodica. Spare batteries…lots of spare batteries.

8. Throw in a Merck Manual to reinforce the idea of modern medical practice and the germ theory.

If you still have space, throw in an explanation of Western musical notation and some of the greatest hits from the last 2000 years. Already have the melodica. (IP issues take on truly Olympian proportions…)

Step 1: get a small army of scribes to make several copies of the encyclopedia, mineral atlas, dictionary and Merck Manual. Salt a couple away in some desert caves.

Step 2.: create a “mystery cult” surrounding the military techs. Going from spears and bows to ranged weapons like rifles and shells will be very destabilizing, and society might collapse before the good stuff happens.

Maybe put everything into “mystery religion” to systematically spread and control the information while managing the accelerated development. With the Bible and Koran you have readymade texts, and the history of Christianity and Islam provides a roadmap to their development. Maybe edit the holy texts to put a little more focus on loving one’s fellow man and the Golden rule, and a little more clarity about slavery, religious persecution, etc..

Fun to think about.

Plastics