The nature of Vulcan is connected with religious ideas concerning fire; the Roman concept of Vulcan seems to associate him to both the destructive and the fertilizing powers of fire. In the first aspect, he is worshipped in the
Volcanalia, to avert its potential danger to harvested wheat. His cult is located outside the boundaries of the original city to avoid the risk of fires caused by the god in the city itself. This power is, however, considered useful if directed against enemies and such a choice for the location of the god's cult could be interpreted in this way too. The same idea underlies the dedication of the arms of the defeated enemies, as well as those of the surviving general in a
devotion ritual to the god. Through comparative interpretation this aspect has been connected by Dumézil to the third or defensive fire in the theory of the three Vedic sacrificial fires. In such theory three fires are necessary to the discharge of a religious ceremony: the hearth of the landlord, which has the function of establishing a referential on Earth in that precise location connecting it with Heaven; the sacrificial fire, which conveys the offer to Heaven; and the defensive fire, which is usually located on the southern boundary of the sacred space and has a protective function against evil influences. Since the territory of the city of Rome was seen as a magnified temple in itself, the three fires should be identified as the hearth of the landlord in the temple of Vesta (); the sacrificial fires of each temple, shrine or altar; and the defensive fire in the temple of Vulcan. Another meaning of Vulcan is related to male fertilizing power. In various Latin and Roman legends he is the father of famous characters, such as the founder of
Praeneste Caeculus,
Cacus, a primordial being or king, later transformed into a monster that inhabited the site of the
Aventine in Rome, and Roman king
Servius Tullius. In a variant of the story of the birth of
Romulus the details are identical even though Vulcan is not explicitly mentioned. : in the center is
Mercury holding the
caduceus and on the right
Juno sits on her throne. Behind her
Iris stands and gestures. On the left is Vulcanus (
blond figure) standing behind the wheel, manning it, with Ixion already tied to it.
Nephele sits at Mercury's feet; a Roman fresco from the eastern wall of the
triclinium in the
House of the Vettii,
Pompeii,
Fourth Style (60–79 AD). Some scholars think that Vulcan might be the unknown god who impregnated goddesses
Fortuna Primigenia at Praeneste and
Feronia at
Anxur. In this case, he would be the father of
Jupiter. This view, however, is in conflict with that which links the goddess to Jupiter, as his daughter () and his mother too, as , meaning "primordial". In all of the above-mentioned stories, the god's fertilizing power is related to that of the fire of the house hearth. In the case of Caeculus, his mother was impregnated by a spark that dropped on her womb from the hearth while she was sitting nearby.
Servius Tullius' mother
Ocresia was impregnated by a male sex organ that miraculously appeared in the ashes of the sacrificial ara, at the order of
Tanaquil,
Tarquinius Priscus' wife.
Pliny the Elder tells the same story, but states that the father was the
Lar familiaris. The divinity of the child was recognized when his head was surrounded by flames and he remained unharmed. Through the comparative analysis of these myths, archaeologist
Andrea Carandini opines that
Cacus and
Caca were the sons of Vulcan and of a local divine being or a virgin as in the case of Caeculus. Cacus and Caca would represent the metallurgic and the domestic fire, projections of Vulcan and of
Vesta. These legends date back to the time of preurban
Latium. Their meaning is quite clear: at the divine level Vulcan impregnates a virgin goddess and generates Jupiter, the king of the gods; at the human level he impregnates a local virgin (perhaps of royal descent) and generates a king. The first mention of a ritual connection between Vulcan and Vesta is the of 217 BC. Other facts that seem to hint at this connection are the relative proximity of the two sanctuaries and
Dionysius of Halicarnassus' testimony that both cults had been introduced to Rome by
Titus Tatius to comply with a vow he had made in battle.
Varro confirms the fact. Vulcan is related to two equally ancient female goddesses,
Stata Mater, perhaps the goddess who stops fires and
Maia.
Herbert Jennings Rose interprets Maia as a goddess related to growth by connecting her name with IE root *MAG.
Macrobius relates Cincius' opinion that Vulcan's female companion is Maia. Cincius justifies his view on the grounds that the sacrificed to her at the Kalendae of May. In Piso's view, the companion of the god is
Maiestas. According to
Gellius as well, Maia was associated with Vulcan; and he backs up his view by quoting the ritual prayers in use by Roman priests. Vulcan is the patron of trades related to ovens (cooks, bakers, confectioners) as attested in the works of
Plautus,
Apuleius (the god is the cook at the wedding of
Cupid and Psyche) and in Vespa poet's short poem in the
Latin Anthology about the litigation between a cook and a baker. ==Sons==