When was Rome the most powerful?

The Romans began to spread over the Italian peninsula during the fifth century BCE. The Roman Republic was transformed into an empire effectively in 44 BCE, and literally in 27 BCE. The Empire reached its height of expansion in 117 AD. At that time, the Roman territory reached from Scotland in the Northeast to the Euphrates River in Southwest Asia, encircling the Mediterran.

ean Sea.

http://en.wikipedia.org/wiki/Roman_Empire