What did Romulus do when Remus was captured by Amulius?

Romulus gathered a group of shepherds and went to Alba Longa to liberate Remus. He met Numitor, his grandfather who had been the king of the city and deposed by his brother Amulius. They worked out that the twins were his grandsons. Romulus, with the help of Numitor, set out to take Alba Longa. Once there he was joined by people who had been mobilised by Remus, who had been liberated. They twins killed Amulius and restored Numitor to the throne. However, they decided not to stay in Albal Longa and to found a new city where they grew up.