Romulus and Remus were twins
     Romulus the first the Roman king

Mythical Alba Longa
The mythical story of Romulus and Remus started in the now long destroyed place Alba Longa. Probably it never existed.
Numitor was king of Alba Longa. His brother Amulius drove him out and seized the kingdom. The daughter of his brother, Rea Silvia, had he chosen as a priestess of Vesta, in order to prevent her getting offspring.

Mars is the father!
The girl however got pregnant anyway, but declared that father be no one less than Mars, the god of war. But not all women get away with declaring her child, a child from god. Amulius had her thrown into prison and the twins he ordered to be thrown into the Tiber.

Floating in a basket
The Tiber had over flown its banks and the the servant, not able to reach the mainstream, left the boys in a basket in a pool near the river. But little boys in floating baskets tend to become princes. The twin was found by a lupa (she wolf) that fed them. Then they were found for the second time, by Faustulus, the keeper of the king's herd, who took them home.

A she wolf or a whore?
His wife Larentia also a lupa (whore) raised the Romulus and Remus as if they were her own.
See Ab urbe condita 1.4,
where Livius explains that this double meaning of the the word probably caused this strange story.

Nobility shows
The boys grew up and one day they met Numitor. Immediately Numitor recognized the boys. Now the boys knew the truth about their royal origin. They killed Amulius and restored their grandfather at his throne.

Let the gods decide
Now the Romulus and Remus wanted to found a city of their own, but couldn't agree  which of them would be come the king of the new city.
They agreed to let the gods decide. In order to do this Romulus sat upon the Palatine hill and Remus upon the Aventine, as observation points for the auguries

The first or the most?
Remus observed the first omen: 6 vultures. His friends ran to Romulus to tell him that Remus would be the king. At the very moment they arrived 12 vultures to show them self to Romulus. Now both claimed their right to be king.

Murder!
They started both to build a city of their own on the hill where they had been sitting.
When Remulus visited his brother, he leaped over the city wall being built, saying that it was not very high. Seeing and hearing this, Romulus lost his temper and killed his brother shouting:"Nobody leaps over my walls!"

Patres, fathers of the city
Now Romulus was the sole king and built the city as he saw fit. He selected 100 of the best men there were and made them senator. They were called patres and would be indeed the fathers of the patricians: the nobles of the city.

How to get women into the city
When the city became more powerful, they came to the insight that there was a lack of women. Since the neighboring cities refused to allow intermarriage, Romulus came up with a plan.
All the neighbors were invited for a great festival. One of the invited people, the Sabines, came with their families. In the midst of the party the Roman carried away the maidens of the Sabines and would marry  them.  In the war that was a result of this action, the maidens, now Roman wives, interfered and made the parties make peace. (For a while).

Deified Romulus
A couple of years later, Romulus is said to have disappeared in the midst of a big thunder cloud. After that he is deified and worshipped as Quirinus.