Greek and Roman pantheon look very similar, but for different names.

The origins of Roman Religion

Most of the Roman gods and goddesses were a blend of several religious influences. Many were introduced via the Greek colonies of southern Italy. Many also had their roots in old religions of the Etruscans or Latin tribes.
Often the the old Etruscan or Latin name survived but the deity over time became to be seen as the Greek god of equivalent or similar nature. And so it is that the Greek and Roman pantheon look very similar, but for different names....  An example of such mixed origins is the goddess Diana to whom the Roman king Servius Tullius built the temple on the Aventine Hill. Essentially she was an old Latin goddess from the earliest of times.
Before Servius Tullius moved the center of her worship to Rome, it was based at Aricia.
There in Aricia it was always a runaway slave who would act as her priest. He would win the right to hold office by killing his predecessor. To challenge him to a fight he would though first have to manage to break off a branch of a particular sacred tree; a tree on which the current priest naturally would keep a close eye. From such obscure beginnings Diana was moved to Rome, where she then gradually became identified with the Greek goddess Artemis... It could even occur that a deity was worshipped, for reasons no-one really could remember. An example for such a deity is Furrina. A festival was held every year in her honour on 25 July. But by the middle of the first century BC there was no-one left who actually remember what she was actually goddess of.