Of such notions, the products of outward abstraction--of the homeliest simplicity, sometimes venerable, sometimes ridiculous--Roman theology was in substance made up.
Conceptions such as sowing (-saeturnus-) and field-labour (-ops-) ground (-tellus-) and boundary-stone (-terminus-), were among the oldest and most sacred of Roman divinities.

Perhaps the most peculiar of all the forms of deity in Rome, and probably the only one for whose worship there was devised an effigy peculiarly Italian, was the double-headed lanus; and yet it was simply suggestive of the idea so characteristic of the scrupulous spirit of Roman religion, that at the commencement of every act the "spirit of opening" should first be invoked, while it above all betokened the deep conviction that it was as indispensable to combine the Roman gods in sets as it was necessary that the more personal gods of the Hellenes should stand singly and apart.( 4) Of all the worships of Rome that which perhaps had the deepest hold was the worship of the tutelary spirits that presided in and over the household and the storechamber: these were in public worship Vesta and the Penates, in family worship the gods of forest and field, the Silvani, and above all the gods of the household in its strict sense, the Lases or Lares, to whom their share of the family meal was regularly assigned, and before whom it was, even in the time of Cato the Elder, the first duty of the father of the household on returning home to perform his devotions.

In the ranking of the gods, however, these spirits of the house and of the field occupied the lowest rather than the highest place; it was--and it could not be otherwise with a religion which renounced all attempts to idealize--not the broadest and most general, but the simplest and most individual abstraction, in which the pious heart found most nourishment.
This indifference to ideal elements in the Roman religion was accompanied by a practical and utilitarian tendency, as is clearly enough apparent in the table of festivals which has been already explained.

Increase of substance and of prosperity by husbandry and the rearing of flocks and herds, by seafaring and commerce--this was what the Roman desired from his gods; and it very well accords with this view, that the god of good faith (-deus fidius-), the goddess of chance and good luck (-fors fortuna-), and the god of traffic (-mercurius-), all originating out of their daily dealings, although not occurring in that ancient table of festivals, appear very early as adored far and near by the Romans.

Strict frugality and mercantile speculation were rooted in the Roman character too deeply not to find their thorough reflection in its divine counterpart.
Spirits Respecting the world of spirits little can be said.