And Jana, a pair of ancient Latin divinities, who were worshipped as the sun and moon, whence they were regarded as the highest of the gods, and received their sacrifices before all the others. (Macrob. Sat. i. 9; Cic. de Nat. Deor. ii. 27.) The name Janus is only another form of Dianus, and Jana of Diana; but the ancients connected it also with janua (door), for it was also applied to a covered passage with two entrances, as the Janus medius in the forum. (Heindorf, ad Horat. Sat. ii. 3. 18.) The fact of Jana being identical in import with Luna and Diana is attested beyond a doubt by Varro (de Re Rust. i. 37). We stated above that Janus was regarded as identical with Sol, but this does not appear to have been the case originally, for it is related that the worship of Janus was introduced at Rome by Romulus, whereas that of Sol was instituted by Titus Tatius (August. de Civ. Dei, iv. 23), and the priority of the worship of Janus is also implied in the story related by Macrobius (Sat. i. 9). Hence we must infer that the two divinities were identified at a later period, and that in such a manner that the separate idea of Sol was lost in that of Janus, for we find few traces of the worship of Sol, while that of Janus acquired the highest importance in the religion of the Romans. Numa in his regulation of the Roman year called the first month Januarius, after Janus, the highest divinity, presiding over the beginning of all things: the same king dedicated to Janus the passage called Janus, which was opened in times of war, and closed when the Roman arms rested. (Liv. i. 9; Varro, de Ling. Lat. v. 164.) This passage (commonly, but erroneously, called a temple), with two entrances, was usually called Janus Geminus, Janus Bifrons, Janus Quirinus or Portae Belli (Horat. Carm. iv. 15. 8; Virg. Aen. vii. 607), and stood ad infimum Argiletum, close by the forum. Atemple of Janus was built by C. Duilius in the time of the first Punic war: it was restored by Augustus, and dedicated by Tiberius. (Tacit. Ann. ii. 49.) Niebuhr (Hist. of Rome, vol. i. p. 292, 3d edit.) explains the objects of the earliest Janus (and those of the others in a similar manner) as follows: "When the two cities (that of the Romans on the Palatine, and that of the Sabines on the Quirinal) were united on terms of equality, they built the double Janus, on the road leading from the Quirinal to the Palatium, with a door facing each of the cities, as the gate of the double barrier which separated their liberties. It was open in time of war, that succour might pass from one to the other, and shut during peace; whether for the purpose of preventing an unrestricted intercourse, out of which quarrels might arise, or as a token that, though united, they were distinct." But if this had been the case, the two gates would necessarily have faced the north and south, whereas, according to the express testimony of Procopius (Bell. Goth. i. 25), the two gates, as well as the two-faced statue of Janus, which stood in the passage, faced the east and west. It is therefore more probable that the Janus Geminus originally was not an ordinary gate of the city, but, like the later porta triumphalis, used only on certain occasions, viz. armies marching out against an enemy and returning from their campaign, passed through it: hence it was open in war, indicating symbolically that the god too had gone out to assist the Roman warriors, and shut in time of peace that the god, the safeguard of the city, might not escape. (Ov. Fast. i. 281 ; Macrob. Sat. i. 9.) This covered gate is in later times often called a temple, but probably in a wider sense of the word, that is, as a sacred place, containing the statue of Janus. A bronze statue of the god, five cubits in height, existed as late as the time of Procopius.
The earliest representations, however, appear to have been the two-faced heads, which are frequently seen on Etruscan medals found at Volaterrae. A statue with four faces was brought to Rome after the conquest of the Etruscan town of Falerii (Serv. ad Aen. vi. 607; Macrob. l. c.), and was there imitated, for one of the same kind existed at Rome in the forum of Nerva as late as the time of Laurentius Lydus. (De Mens. iv. 1.) Whether the Etruscan divinity with two or four faces was originally the same as the Roman Janus is uncertain, but it was at any rate very natural for the Romans to see in him their own Janus, and to identify the two. The identity of Janus with the Sun was commonly expressed by his indicating with the fingers of the right hand the 55 (Plin. H. N. xxxiv. 7), and in later times by his counting in his right hand 300 pebbles, and in his left 65. (L. Lydus, de Mens. i. 4.) In some representations he held in his right hand a staff or sceptre, and in his left a key (Ov. Fast. i. 99; cornp. L. Lydus, l. c.), by which he is symbolically described as the god who had power over the entrance of heaven (Ov. Fast. i. 125); hence he had the surnames of Patulcus or Patulcius, and Clusius or Clusiviuns. (Ov. Fast. i. 129; Serv. ad Men. vii. 610; Macrob. l c.; L. Lydus, de Mens. iv. 1.)
Although in the classical age the Romans themselves avowed that Janus was peculiar to themselves (Ov. Fast. i. 90), yet we find at a later period, when Janus was regarded as the god of all entrances and gates, that he was identified with Apollo Thurais. (Macrob. l. c.) We pass over a series of arbitrary etymological and philosophical speculations (see Varro, ap. August. de Civ. Dei, vii. 9; Festus, s. v. Chaos), and merely remark, that no nation of antiquity attributed such importance to the beginning of a work or undertaking as the Romans, who believed that the progress and success of a thing had some magic connection with its beginning. (Gellius, v. 12; Plin. H. N. xxxvi. 5.) Janus was the god of the beginning of everything: he protected the beginning of all occupations and actions as well as of human life, whence he was called Consivius (a conserendo, or consationibus, Macrob. Sat. i. 9; Tertull. ad Nat. ii. 11). Hence, whenever a civil or military undertaking did not succeed, it was attributed to some fault in the manner of beginning it, and was frequently commenced afresh. (Ov. Fast. i. 179.) It was indeed Jupiter who by augury sanctioned every undertaking, but its beginning depended on the blessing of Janus; hence these two divinities were invoked first in every undertaking, and in all prayers their names were mentioned first. The fact of the name of Janus being pronounced even before that of Jupiter, and that according to tradition Janus was in Italy before any of the other gods, and that he dedicated temples to them (Macrob. l. c.; Ov. Fast. i. 70; L. Lydus, de Mens. iv. 2; Aur. Vict. de Orig. Gent. Rom. 3), is perfectly in accordance with the idea of the god, he being the beginning of every thing; but it does not follow that on this account he was considered superior or more powerful than all the other gods. As he presided over the beginning of the year, the people offered sacrifices to him on the first day of the year, and priests offered sacrifices to him on twelve altars, as the beginner of the twelve months, and prayed to him at the commencement of every day. (Varro, ap. Macrob. l. c.; P. Vict. Reg. Urb. xiv.) As the kalends of every month were sacred to Juno, Janus was surnamed Junonius, and in reference to his presiding over the beginning of every day, he was called Pater Matutinus. On new year's day, which was the principal festival of the god, people took care that all they thought, said, and did, was pure and favourable, since every thing was ominous for the occurrences of the whole year. Hence the people wore festive garments, abstained from cursing, quarrelling; they saluted every one they met with words of a favourable import, gave presents to one another, and performed some part of what they intended to do in the course of the year, auspicandi causa. (Columella, de Re Rust. xi. 2; Senec. Epist. 83; Ov. Fast. i. 169.) The presents connumber 300, and with those of the left the number sisted of sweetmeats, such as gilt dates, figs, honey cakes, and copper coins, showing on one side the double head of Janus and on the other a ship. (Ov. Fast. i. 185, &c., 230; Plin. H. N. xxiii. 3, 13; Martial, viii. 33, xiii. 27; Plut. Quaest. Rom. p. 274; Macrob. Sat. i. 7; L. Lydus, de Menes. iv. 2.) The general name for these presents was strenae. The sacrifices offered to Janus consisted of cakes (called janual), barley, incense, and wine. (Ov. Fast. i. 75, 128, 172; Festus, s. v. janual; L. Lydus, de Mens. iv. 2; Hartung, Die Relig. d. Röm. vol. ii. p. 218, &c.)