He was famous for discovering the real orbit of the planets and many others
The reasons that totalitarian states arose after WWI are many. The economy of many countries was shattered by the costly conflict (especially Germany, being forced to pay reparations), causing socialist and communist ideas to flourish. The scars on society left by the war allowed for embittered populations to be swayed by good orators that could play to the crowd's emotions; Hitler liked to appeal to a desire for revenge in the German people, for instance. Also, as mentioned before, new ideas spread during the war, many involving government, often causing factions to fight over a country, with one finally coming on top, usually led by a single, charismatic individual.
Not sure if this will help but here's what I put:
They developed lots of new techniques for buildings and constructions. They also brought about incredibly well put together aqueducts that ran for miles. They built military roads and they are still a basis for many things that we build today.
They talked about equality under the law, and also came up with The Twelve Tables, which are very well known today. Christianity was banned in ancient Rome and Christians were punished for a very long time because of this. They were even fed to lions as entertainment.
