The kingdom of Alba Longa was ruled by the wicked king, Amulius. Amulius fought his brother, Numitor, and sent him into exile. Amulius forced Numitor's daughter, Rhea Silvia, to become a Vestal Virgin. Vestal Virgins were not allowed to marry and have children.
One day Mars, the god of war, saw Rhea Silvia and fell in love with her. Some time later she gave birth to twin boys. Amulius ordered his slave to throw the two twins into the River Tiber. But the slave left the twins in their cradle to give them a chance. They floated down the river. A she-wolf rescued the two babies and looked after them.
A shepherd called Faustulus saw the she-wolf with the baby boys. He took them home to his wife and they called them Romulus and Remus. When they grew up the boys became shepherds like Faustulus. One day they had a fight with some shepherds who looked after Numitor's sheep. Remus was arrested and sent to Numitor as a prisoner. When Numitor heard the story he realised that Remus was his grandson! He told Romulus and Remus what had happened to him and their Mother.
Romulus and Remus attacked their Great Uncle Amulius and killed him. Now Romulus and Remus lived with their grandfather in Alba Longa, but they got bored and missed the countryside where they grew up. They decided to move back to the place where Faustulus had found them and build their own city on the banks of the River Tiber.
But the twins argued over where the city should be built. Romulus wanted to build it on the Palatine Hill and Remus wanted to build it on the Capitoline Hill. In the end they built two cities! The arguing didn't stop. Remus teased his brother about the height of his city walls, saying they were too low. The brothers had a fight and Romulus killed Remus. Romulus became King of the new city, which was called Rome in his honour.