They were descendants of Aeneas through their mother's father who was a king. The identity of their father was unknown, but it is said that it was the god of Mars or the demigod Hercules.
Romulus saves Remus
The king Amulius imprisoned Rhea Silvia and ordered the twins' death either by live burial, exposure, or being thrown into the Tiber River. The River God slowed the river and caused the basket to get caught in the roots of a tree.
Creation of Rome/Death of Remus
The twins were discovered by a she-wolf who took care of them and fed them until they were found by a shepherd. They were also raised to be shepherds.
Rome Thrives/Death of Romulus
Remus got into a fight with other shepherds which led to him being captured by the king. Romulus was able to free him and kill the king.
Romulus built a wall and Remus made fun of him for it. Out of anger, Romulus killed Remus. Romulus continued to build a city which he called Roma after himself.
Government systems were created, but there were mostly men that occupied Rome so they had to steal women. This led to a war that Romulus fought and won. Romulus then mysteriously disappeared in a storm in 717 BCE. There are three myths about his death which were that he just disappeared, he was killed, and he ascended to the heavens to become a god.