A closer look at the Roman gods
Difference between Greek and Roman gods
Many people think that the Roman gods and Greek gods and goddesses were about the same, but there is a real difference. The Greek created their gods, people alike, and made a lot of beautiful stories about them. The Roman belief was merely based on animism; the belief that spirits (Anima-soul) not only exist in humans but in animals and plants and rocks as well.
So if a farmer offered to Ceres he would also send his prayers to Concus for the storage of his grain or Priapus for the fertility of his land , etc. After the Romans came in contact with the Greek world, they admired their culture and imported many of their gods.
For a list of the Roman and Greek gods go here.
Romans were tolerant in their believes
Like all the ancient peoples around the mediterranean, Romans were tolerant in their believes and accepted easily other deities from the cultures surrounding them. Especially after they they had conquered or admired a culture. If such a deity had about the same qualities as a one of the Romans, the Romans would identify that one with the name of their own deity. At the beginning of the 2e Punic war, Hannibal Barca went to Gades (mod. Cadiz) in order to sacrifice to Melqart, but Titus Livius writes that Hannibal sacrificed to Hercules. In the list are the gods shown with their counterparts in other religions.
In all the wars that the Romans fought, there was not even one that had a religious reason. In the meantime their pantheon grew and grew. In the list under the links below are 70 Roman deities. I don't think the list is complete.
A number of them are "imported" gods that kept their own name, like the Egyptian goddess Isis. Isis was very popular amongst women. More about Isis and other Egyptian gods
In every house there was a place to offer to the spirits of that particular house: the Lares. Such an altar was called the Lararium. The Lares were connected to the house and would stay there if the family left.
Penates belong to the family
The Penates on the other hand were connected to a specific family. We can read in the Aeneis that Aeneas not only took his family but also the Penates. He would bring them al the way from Troy to Alba Longa in Latium Italy.
When ages later the Romans conquered Alba longa they took those Penates and brought them back to Rome. After all, they were the descendants from Troy