The God of war, Mars, had twin boys with princess Rhea Silvia.
Rhea had gone against her vows of celibacy, so King Amulius imprisoned Rhea Silvia and ordered the twins' to be thrown in the Tiber River. He ordered a servant to carry out the death sentence, but the servant took pity on the twins and spared their lives by putting them into a basket onto the Tiber River.
The twins basket caught in the roots of a nearby fig tree. There a she-wolf or lupa, found them and took care of them.
They were then found by a shepherd and the shepherd took them in and raised them to adulthood.
The twins decided they wanted to establish a city of their own where the wolf had found them. They fought over where to place their city.
Romulus became angry and killed Remus. Romulus continued to build his city. He officially founded his city and named it Rome, after himself.