Romulus gathered some shepherds to rescue his brother. They ended up killing the king.
When the city learned who the boys were, they offered to crown them as joint kings. they turned down the crowns because they wanted to found their own city. The twins left and set out to find the perfect spot for their city.
Thank you but no.
The twins eventually came to the place where Rome is located today. They both liked the general area, but each wanted to place the city on a different hill.
They agreed to wait for a sign from the gods, called an augury, to determine which hill to use. Remus saw the sign of six vultures first, but Romulus saw twelve. Each claimed to have won.
Romulus went ahead and started building a wall around his hill. However, Remus was jealous and began to make fun of Romulus' wall.
At one point Remus jumped over the wall to show how easy it was to cross.