I'd say pollution or disease.
Answer:
The Roman Empire
As a polity it included large territorial holdings around the Mediterranean Sea in Europe, Northern Africa, and Western Asia ruled by emperors. From the accession of Caesar Augustus to the military anarchy of the third century, it was a principate with Italy as metropole of the provinces and the city of Rome as sole capital (27 BC – 286 AD). Although fragmented briefly during the military crisis, the empire was forcibly reassembled, then ruled by multiple emperors who shared rule over the Western Roman Empire (based in Milan and later in Ravenna) and over the Eastern Roman Empire (centred on Nicomedia and Antioch, later based in Constantinople). Rome remained the nominal capital of both parts until 476 AD, when the imperial insignia were sent to Constantinople, following the capture of Ravenna by the barbarians of Odoacer and the subsequent deposition of Romulus Augustulus. The fall of the Western Roman Empire to Germanic kings, along with the hellenization of the Eastern Roman Empire into the Byzantine Empire, conventionally marks the end of Ancient Rome and the beginning of the Middle Ages.
They slowed work down. This was to to make a statement, and show the slave owners they didn't want to be slaves anymore.
it established a faster way of transportation
John Dalton - The idea of an atom- the smallest component of matter that could not be divided further - was proposed around the year 400 BC. However, Aristotle did not like the idea. He claimed that all matter was composed of various proportions of elements like air, water, earth and fire. However, he had no experimental evidence to prove it. It was only when John Dalton (an English chemist, physicist and meteorologist), after experimenting with various gases, discovered that all matter is, in fact composed of extremely small particles called atoms, that the atomic model was first accepted worldwide.
