You are a modern chemist and metallurgist and unexpectedly get sent back in time to the era of Caesar Octavius Augustus. After spending a couple years learning ancient Latin, what changes or improvements could you offer to Roman society?

You know how to make modern metals but could the Romans know how to find the components to make more modern metal alloys? Would they have the heat sources necessary to smelt ores to make modern alloys? Could you at least encourage them to not put lead in their water pipes to cut down on lead poisoning? Could you improve their iron to make something closer to modern steel to make their armor and weapons better? Could you get them to make crude bronze cannons that could be used in sieges or siege defense?

Could you set up chemical disinfectants to help improve food preparation cleanliness and wound care? You do not have advanced medical knowledge but you know cleanliness and germ control could help a LOT! Could you offer them some basic ideas on fertilizers and pesticides? The assumption is you are an expert and very knowledgable but you have no text books or resources you were able to take with you, all you have is your memory. Would that be enough and what would be the most useful? (My personal choice would be fertilizers and disinfectants.)


closed as too broad by Ash, Cyn, StephenG, Starfish Prime, pluckedkiwi Jul 22 at 13:53

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    $\begingroup$ Lot of questions... $\endgroup$ – puppetsock Jul 19 at 14:34
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    $\begingroup$ Given that just about all emperors were called Caesar Augustus, what exact timeframe do you have in mind? Do you mean specifically Imperator Caesar Divi Filius Augustus, aka Octavian? And the answer is quite obviously yes, one can; not immediately, of course, because such things take time. In real history the Romans achieved all this, in about 20 centuries. $\endgroup$ – AlexP Jul 19 at 14:41
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    $\begingroup$ Lest Darkness Fall by L. Sprague de Camp, 1941; the first book in the subgenre of alternate history where one or more smart persons displaced in time do their best to accelerate social, technological and scientific progress. $\endgroup$ – AlexP Jul 19 at 14:48
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    $\begingroup$ Right "what would be the most useful?" is, by definition, Primarily Opinion Based, it's not a question with an objective answer. $\endgroup$ – Ash Jul 19 at 15:30
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    $\begingroup$ Welcome to Worldbuilding.SE Robert, glad you found us. Please check out our tour and help center. It sounds like you have an interesting novel to write but, as a WB question, it's rather broad. We like our questions one at a time here. Check for duplicates but I think you'd be better off dropping the chemistry part and just focusing on lead pipes or modern steel. Or just do disinfectants and nothing else. You can ask followup questions later if you wish. $\endgroup$ – Cyn Jul 19 at 16:12

The Bessemer Process. In principle, the engineering was within range of Roman technology, and it would represent a monumental change in, well, everything. Not just producing steel, but producing steel in mass quantities. Not just weapons but bridges and tools and armour.

Then of course, the old favourite, black powder. The Romans would have taken to making things go BOOM! like a fish to water. And again, not just for weapons. Being able to break mass quantities of rock would have been very useful for their construction projects.

  • $\begingroup$ Bessemer process is not a low hanging fruit. Blast furnace has to be built first. $\endgroup$ – Alexander Jul 19 at 22:36
  • $\begingroup$ You do it all in one step. The Chinese had blast furnaces in the first century CE, so it's not as though it's a huge technological leap from what the Romans were already using. $\endgroup$ – Keith Morrison Jul 20 at 18:48
  • $\begingroup$ This "one step" is a much bigger step than the other one with black powder. $\endgroup$ – Alexander Jul 21 at 7:53

The Romans could cast bronze with great skill. Cannons and early primitive guns were often made from bronze. Showing the Romans how to make gunpowder and bronze cannons would have been entirely possible. Blackpowder is just sulfur, saltpeter, and charcoal. A cannon is just a metal (bronze) tube with one end closed, a tiny hole to touch a red hot poker to, and something the same size as the tube shoved in on top of the powder. Early handguns were just mini-cannons affixed to a wooden handle.

All components, skills, and techniques to make cannons and primitive handguns existed in Rome, just nobody had ever thought of combining them in that way before. Introducing the Romans to gunpowder is the simplest and most plausible and impactful chemistry introduction you could make.


In order to make the most rapid progress, Your guy would have to start with weapons.

The reasoning behind this is that while you could help with a great many things, The Gaulles, the Teutons, and the Huns are out there RIGHT NOW. Superior weapons are both symbolic and practical. A legion armed with swords and spearheads that don't readily break when going up against crazy proto-vikings would give a solid advantage. Maybe not as much as an advantage as you might think, but enough to get the attention of some very powerful patrons. Once you get the metallurgy part working, you could use some modern ideas to increase production efficiency.

Things like fertilizer and disinfectants are massively useful, of course, but they aren't as immediate as the barbarian at the gate. You would have to wait until the immediate threats are dealt with before getting to the things that take longer to be realized. Of the 2, fertilizers are where I would put focus next, in between various smaller projects for your patrons. Endeavor to get the attention of a patron who makes his money off of crops and land. Get him to give you a small field to play with fertilizer in for a season or two and show him how much higher the yield of that field is much higher than others. Give them actual proof. This may take several seasons.

These two steps might give you enough of a reputation as a sage to really begin branching out. Then you could begin writing down what you have done and begin doing the most important thing with accelerating a civilizations advancement. You need to start teaching! You are one guy with a limited life span. Start teaching and within a generation, there are several guys who can teach even more people. It's the dissemination on knowledge that will propel things forward overall.

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    $\begingroup$ At the time of Augustus, Teutons were no longer an issue, Huns might not have existed yet, and Gauls were effectively dealt with using conventional arms. Just my 2 cents. $\endgroup$ – Alexander Jul 19 at 16:12
  • $\begingroup$ @Alexander: The Gauls were actually putting a lot of effort into becoming good Romans... Note that it is not uncommon to use "Teutons" to refer to the Germanic peoples in general, and Germanic peoples were very much a problem in Octavian's time. $\endgroup$ – AlexP Jul 20 at 6:50
  • $\begingroup$ Being a sage might actually work against you, the biggest limit the romans had on their technology was how cliquish they were, pursuing modern scientific methods are impossible with an authoritative knowledge mindset. Falsifiability and reproducibility make advancement lightning fast. $\endgroup$ – John Jul 20 at 15:00
  • $\begingroup$ @alexander OK, so I was 400 years short of the Huns, Teutons, as I understand were a constant thorns in the side of any general trying to go north for a long time. Too many tribes to simply crush outright. Gauls were readily handled more due to the tactics than the quality of the weaponry. However, with better weapons, you win battles with fewer casualties on your side and any decent general counts that as a very good thing. Even if they were already subdued, there was enough in living memory for the Gauls to be a concern. $\endgroup$ – Paul TIKI Jul 22 at 13:45
  • $\begingroup$ If your concern is an immediate military campaign, spending years figuring out how to manufacture a new kind of weapon, developing production facilities to produce them in meaningful quantities, training the officers and soldiers in their effective use, and developing the logistical train to keep it supplied in the field on campaign is not useful. Teaching them about bacteria and sanitation can have an immediate effect, which is especially vital when you consider how many soldiers died of disease (often more than those who died of wounds inflicted by the enemy). $\endgroup$ – pluckedkiwi Jul 22 at 14:00

You don't start with weapons, if you want to improve military power you start with medicine, logistics, and infrastructure.

  1. sulfonamide, the first antibiotics, producible with basic chemistry. The romans had mobile hospitals to support troops, now most of your casualties live, suddenly you are the immortal army. Germ theory will help make this even more effective.

  2. canning, early canning used glass and pottery. food that does not spoil turns a slow moving army into an something that moves so fast they will take on an almost mythological standing. It also allows for fighting during winter, which would make your armies unstoppable at the time. You are right that artificial fertilizer will improve roman farming but canning and the wastage it prevents will as well.

  3. Radio, simple radios are not hard to make, well within the roman capabilities. All of a sudden your legions can communicate while in the field even at a distance. This means they can coordinate This will make your army act as though it were many times larger without having to feed anymore people. It really compliments the roman military style as well.

  4. explosives, gunpowder and dynamite are easy to make with the right knowledge. Forget about weapons the real use for explosives is mining, cheap metal and coal improves all aspects of roman life including agriculture (steel plows) and allows for a later more ambitious invention, steam power.

  5. the telescope, the romans loved glass, making clear optical glass is hard but within their capabilities, Militarily it allows both ground and naval troops to figure out what the enemy is doing, each "spyglass" will be expensive but any commander worth his salt will see the value.

  6. The blast furnace, all that coal and iron you are mining now you can put it to use, suddenly instead of soldiers using rare expensive materials like bronze they have cheap abundant iron, add the bessemer process and you have cheap steel, incidentally this also finally makes guns possible.

As a side note just introducing the scientific method will help roman life in general, Roman scientific progress was haphazard because they did not focus on falsifiability and reproducibility instead focusing an authoritative interpretations.


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