What items, innovations, etc, that are generally ascribed to the Romans were actually invented by others?

Question

The Romans were arguably the greatest engineers of the Ancient world. But when it came to innovation, the Romans seemed to just steal an idea and improve upon it.

The Arch, toga, columns, and amphitheater were Greek.
Latin came from the Latins of Latium.
The Legions evolved from the Phalanx.

What did the Romans both assimilate and/or improve upon from other civilizations?

Answer 1

The Romans invented cement and developed building techniques that made use of it. They used the arch in domes on buildings and the Colosseum in an innovative ways. They were masters of administration and organization of labor
Egypt used columns and arches long before the Greeks. In western countries it is the Greeks that are given too much credit because we knew little about more ancient civilization until recent times. All civilization build on knowledge of the past and their neighbors.

Answer 2

I once heard that Roman law was widely admired.