Global history please help me.
Answer on What were two reasons for Rome's success in expanding its power across italy?
The most important feat in Rome's success in conquering Italy was its conquest of the Samnites, (in the Abruzzi and Molise regions) their greatest foe in this. This was facilitated by a treaty the Samnites signed that was especially disadvantageous to the Samnites, concerning a boundary along the Larii river.
Rome's further conquests were facilitated by a system of roads leading from Rome to its foederati - so called "allies" - in the rest of Italy. These allowed Rome to send troops to this areas quickly and efficiently.
Her rule was ironically consolidated by a rebellion, which led to the Roman Civil War, also called the Social War. The only way Rome was able to win this war (led by Samnites) was by offering the foederati what they asked for, which was full rights as Roman citizens.
Italy emerged from this war, more united than ever.