Short answers, pulled from the story.
The primary sources for Roman mythology are Virgil's Aeneid, the early books of Livy's history, and Dionysius's Roman Antiquities. Ovid's Fasti, a six-book poem structured by the Roman religious calendar, and the fourth book of elegies by Propertius are also important. Roman myths appear in wall painting, coins, and sculpture as well.
Roman mythology placed greater emphasis on political and moral themes, civic duty, and the relationship between individual integrity and responsibility to the Roman state. Ritual and cultus were primary in Roman religion, whereas narrative myths of divine activity played a more central role in Greek belief. Romans treated many of their mythological narratives as actual history, unlike the Greeks.
The Capitoline Triad consisted of Jupiter, Juno, and Minerva. It replaced the earlier Archaic Triad of Jupiter, Mars, and Quirinus and became central to official Roman religion. Scholars note it as an unusual example within Indo-European religion of a supreme triad formed of two female deities and only one male.
Ovid's Metamorphoses, written during the reign of Augustus, came to be regarded as the canonical telling of Greek myths in the Roman world. The Roman interpretations of Greek myths in that work often had a greater influence on later narrative and pictorial representations than the original Greek sources. The text disseminated classical mythology across Europe through Latin literature from the Middle Ages through the Renaissance.
The Sibylline books were a collection of prophecies pertaining to world history and Rome's destiny. According to legend, Tarquin the Proud purchased them in the late 6th century BC from the Cumaean Sibyl. They were consulted at critical junctures in Roman history, with prophecies appearing suddenly when Rome faced important decisions or crises.
Rome commonly granted the local gods of conquered territories the same honors as earlier Roman state gods. In some cases, the Romans used a formal ritual called evocatio to invite the deities of an enemy power to take up new sanctuaries at Rome. In 203 BC, Rome imported the cult object of Cybele from Pessinus in Phrygia, and the cult of Mithras reached Rome through foreign communities and spread as far as Roman Britain via the Roman army.