Numitar was the King of an empire called Alba Longa, a empire in central Italy. His younger brother, Amulius, grew angry and overthrew Numitar. He locked up Numitar's wife, Rhea Silvia, to become a vestal virgin.
While locked up, Rhea Siliva fell in love with the god of Mars. They had two twin sons, Romulus and Remus. Amulius got worried about the twins overthrowing him, so he put the twins into baskets and into the Tiber River. A she wolf found the twins and raise the kids as their own, until Faustulus, a shepherd, took them home.
Mars, God of War
After Romulus and Remus were grown, they were told of their heiratge. They revolted aganist Amulius to bring Numitor back into power as king of Alba Longa. They then chose to leave Alba Longa to form thier own country.
The borthers decided to go back to where the she wolf found them. The brothers had different ideas for the country, so they each made a wall for their city to see which was best.
Remus teased Romulus about his small wall. Remus even jumped over Romulus' wall to prove to Romulus how little and puny his wall was.
Romulus grew angry and killed Remus. Now being the only ruler he became king of the new country, which he named after himself. That is how Rome was founded.