Why did so much technology that was common in the Roman Empire did not make it into the medieval age?

Question

Examples like aquaducts, sewage, advanced architecture, etcetera

In: 121

Answer 1

There’s a lot in this comment that makes assumptions about the Roman Empire and about the Medieval era. But it can be answered in a general sense: large and complex societies require large and complex societies in order to maintain themselves. When the large and complex society goes away, the systems and technologies that it built and relied upon stop working.

For example, agriculture. City of Rome was so economically important that many generations of farmers/farm workers in, say, Spain, made their living by growing grain as a cash crop to to feed the imperial city. Doing so required multiple complex systems: transportation (moving the grain to ports, ships to move the grain), economic (so they could do this and get paid), legal and political (for resolving disputes); social/commercial (agents whose job it was to co-ordinate – and profit from – the process); as well as urban systems that provided markets, administrative centres, etc. Take one part of it away and the system crumbles. No large population in Rome means no market; no roads means you can’t get it to the ships; no agents means it isn’t worth it for any one farmer to take their grain across the sea in the hope of selling it; no economic system means no way to group the output of many farms together for transport and sale in a cost effective way; no stable political and legal system makes it impossible to trade and transport goods over large distances. The system took decades/centuries to evolve, and without the components that kept it together, it stopped working.

Now apply this to all of the systems built to support cities or massive infrastructural systems like drainage or large buildings, and the problem becomes obvious and circular. You can’t have aqueducts without infrastructure; you don’t generally need aqueducts if you don’t have large urban centres that require water; cities concentrate resources, skills, and political power in order to create infrastructure (not to say that you need cities for this, there are other dynamics, but cities do seem to work well). It works in reverse too: take away the cities, you won’t be need or be able to build and maintain the aqueducts, take away the aqueducts, and the cities run dry.