http://en.wikipedia.org/wiki/Punic_wars
Be sure to read the section about the Third Punic War (scroll down).
How did Roman military orientation and success in war with Carthage contribute to the instability of Roman politics?
2 answers
Also this:
http://en.wikipedia.org/wiki/Roman_history#Roman_Republic
http://en.wikipedia.org/wiki/Roman_history#Roman_Republic