The worship of the Lares at Rome was closely connected with that of the Manes, and that of both was analogous to the hero worship of the Greeks. The name Lar is Etruscan, and signifies lord, king, or hero. The Lares may be divided into two classes, the Lares domestici and Lares publici, and the former were the Manes of a house raised to the dignity of heroes. So long as the house was the place where the dead were buried (Serv. ad Aen. 5.64, 6.152), the Manes and Lares must have been more nearly identical than afterwards, although the Manes were more closely connected with the place of burial, while the Lares were more particularly the divinities presiding over the hearth and the whole house. According to what has here been said, it was not the spirits of all the dead that were honoured as Lares, but only the spirits of good men. It is not certain whether the spirits of women could become Lares; but from the sugrundaria in Fulgentius (De Prisc. Serm. p. xi. ed. Lersch.), it has been inferred that children dying before they were 40 days old might become Lares. (Comp. Nonius, p. 114; Diomed. i. p. 379.) All the domestic Lares were headed by the Lar familiaris, who was regarded as the first originator of the family, corresponding in some measure with the Greek ἥρως ἐπώνυμος, whence Dionysius (4.2) calls him ὁ κατ̓ οἰκίαν ἥρως. (Comp. Plut. De Fort. Rom. 10; and more especially Plin. Nat. 36.70; Plant. Aulul. Prolog.) The Lar familiaris was inseparable from the family; and when the latter changed their abode, the Lar went with them. (Plaut. Trin. 39, &c.)

The public Lares are expressly distinguished by Pliny (Plin. Nat. 21.8) from the domestic or private ones, and they were worshipped not only at Rome, but in all the towns regulated according to a Roman or Latin model. (Hertzberg, De Diis Rom. Pair. p. 47.) Among the Lares publici we have mention of Lares praestites and Lares compitales, who are in reality the same, and differ only in regard to the place or occasion of their worship. Servius Tullius is said to have instituted their worship (Plin. Nat. 36.70); and when Augustus improved the regulations of the city made by that king, he also renewed the worship of the public Lares. Their name, Lares praestites, characterises them as the protecting spirits of the city (Ov. Fast. 5.134), in which they had a temple in the uppermost part of the Via Sacra, that is, near a compitum, whence they might be called compitales. (Solin. 1; Ov. Fast. 5.128; Tac. Ann. 12.24.) This temple (Sacellum Larum or aedes Larum) contained two images, which were probably those of Romulus and Remus, and before them stood a stone figure of a dog, either the symbol of watchfulness, or because a dog was the ordinary sacrifice offered to the Lares. Now, while these Lares were the general protectors of the whole city, the Lares compitales must be regarded as those who presided over the several divisions of the city, which were marked by the compita or the points where two or more streets crossed each other, and where small chapels (aediculae) were erected to those Lares, the number of which must have been very great at Rome. As Augustus wished to be regarded as the second founder of the city, the genius Augusti was added to the Lares praestites, just as among the Lares of a family the genius of the paterfamilias also was worshipped.

But besides the Lares praestites and compitales, there are some other Lares which must be reckoned among the public ones, viz., the Lares rurales, who were worshipped in the country, and whose origin was probably traced to certain heroes who had at one time benefitted the republic. (Cic. De Leg. 2.11; Tib. 1.1. 24.) The Lares arvales probably belonged to the same class. (Klausen, De Carm. Frat. Arval. p. 62.) We have also mention of Lares viales, who were worshipped on the highroads by travellers (Plaut. Merc. 5.2, 22; Serv. ad Aen. 3.302); and of the Lares marini or permarini, to whom P. Aemilius dedicated a sanctuary in remembrance of his naval victory over Antiochus. (Liv. 40.52.)

The worship of the Lares was likewise partly public and partly private. The domestic Lares, like the Penates, formed the religious elements of the Roman household (Cic. De Repub. iv. in fin., ad Fam. 1.9, in Verr. 3.24; Cato De Re Rust. 143); and their worship, together with that of the Penates and Manes, constituted what are called the sacra privata. The images of the Lares, in great houses, were usually in a separate compartment, called aediculae or lararia. (Juv. 8.110; Tib. 1.10. 22; Petron. 29; Ael. Lamprid. Alex. Sev. 28; comp. Dict. of Ant. s. v. Lararium.) The Lares were generally represented in the cinctus Gabinus (Pers. 5.31; Ov. Fast. 2.634), and their worship was very simple, especially in the early times and in the country. The offerings were set before them in patellae, whence they themselves are called patellarii (Plaut. Cistell. 2.2. 55), and pious people e made offerings to them every day (Plaut. Aulul. Prolog.); but they were more especially worshipped on the calends, nones, and ides of every month. (Cato De Re Rust. 143; Hor. Carm. 3.23. 2; Tib. 1.3. 33; Verg. Ecl. 1.43.) When the inhabitants of the house took their meals, some portion was offered to the Lares, and on joyful family occasions they were adorned with wreaths, and the lararia were thrown open. (Plaut. Aulul. 2.8. 15; Ov. Fast. 2.633; Pers. 3.24, &c., 5.31; Propert. 1.1. 132; Petron. 38.) When the young bride entered the house of her husband, her first duty was to offer a sacrifice to the Lares. (Macr. 1.15.) Respecting the public worship of the Lares, and the festival of the Larentalia, see Dict. of Ant. s. v. Larentalia, Compitalia. (Comp. Hempel, De Diis Laribus, Zwickau, 1797; Müller, De Diis Romanorum Laribus et Penatibus, Hafniae, 1811; Schömann, De Diis Manibus, Laribus et Geniis, Greifswald, 1840; Hertzberg, De Diis Romanorum Patriis, sive de Larum atque Penatium tam publicorum quam privatorum Religione et Cultu, Halae, 1840.)