Romulus and Remus are twin brothers and the sons of Mars. Their Grandfather's brother, Amulius, stole the throne and threw the the twins into the Tiber River.
A she-wolf saved the boys from the river and took them in as her own. She gave them milk and cared for them.
They grew a little older, and a shepherd named Faustulus found and took the twins home with him. He looked after them until they grew up.
The twins discovered who they really were and decided to kill Amulius. Their Grandfather took the throne again. After, they decided to build a city. They couldn't decide on a location; therefore, they built their own individual city.
Remus visited Romulus one day. Remus made fun of his wall, and this made Romulus angry.
Romulus killed Remus because he made fun of his wall. He vowed to kill anyone who mocked his city.