[582] In B.C. 45 Cæsar was consul for the fourth time and without a colleague. But he laid down the office before the end of the year, and Quintus Fabius Maximus and C. Trebonius were appointed consuls; the first instance of consuls being appointed for a part of the year, which afterwards became a common practice. (Dion Cassius, 43. c. 46.) The appointment of C. Caninius is mentioned by Cicero (Ad Diversos, vii. 30), who remarks that nobody dined in that consulship, and that the consul was so vigilant that he did not sleep during his term of office: in fact he was consul for only part of a day. An inscription records the consulships of this year. (Note to Cicero in the Variorum edition.)
[583] On the intended Parthian expedition of Cæsar, see Dion Cassius, 43. c. 51.
[584] This design of Cæsar is mentioned by Dion Cassius (44. c. 5), Suetonius (Cæsar, 441), and Plinius (H.N. iv. 4).
[585] This scheme is not mentioned by any other author that I can find. Circæum, or Circeii, as the Romans called it, is the mountain promontory, now Circello or Circeo, between which and Tarracina lies the southern part of the Pomptine marshes. The intended cut must therefore run nearly in the direction of the Via Appia and to the west of it. But considerable cuttings would be required on that more elevated part of the Campagna which lies between the mountains of Alba and the nearest part of the coast. The basin of the Pomptine marshes is bounded by the offsets of the Alban mountains, the Volscian mountains, and the sea. In the central part it is only a few feet above the sea-level, and in some parts it is below it. When a violent south-west wind raises the sea on the coast between Tarracina and Circeo, the water would be driven into the basin of the Pomptine marshes instead of flowing out. There would therefore be no sufficient fall of water to keep the channel clear, even if the head of the cut, where it originated in the Tiber, were high enough; and that is doubtful. The scheme was probably a canal, which with some locks might be practicable; but if the work could be accomplished, it would probably have no commercial advantages.
[586] Pometia is the common Roman form, from which comes the name of the Pometinæ, or Pomptinæ Paludes, now the Pontine Paludi; the site of Pometia is uncertain. That Cæsar intended to accomplish the drainage of this tract is mentioned by Dion Cassius and Suetonius.
Setia (Sezza), noted for its wine, is on the Volscian hills (the Monti Lepini), and on the eastern margin of the marshes. The physical condition of this tract is described by Prony, in his "Description Hydrographique et Historique des Marais Pontins," 4to. Paris, 1822; the work is accompanied by a volume of plans and sections and a map of the district. A sketch of the physical character of this district, and of the various attempts to drain it, is also given in the 'Penny Cyclopædia,'—art. Pomptine Marshes. See also Westphal's two valuable maps of the Campagna di Roma, and his accompanying Memoir, Berlin and Stettin, 1829.
[587] Ostia, the old port of Rome, on the east bank of the Tiber near the mouth of the river. The present Ostia is somewhat farther inland, and was built in the ninth century by Pope Gregory the Fourth. There are extensive remains of the old town, but they are in a very decayed condition. "Numerous shafts of columns, which are scattered about in all directions, remains of the walls of extensive buildings, and large heaps of rubbish covered with earth and overgrown with grass, give some, though a faint, idea of the splendour, of the ancient city, which at the time of its greatest splendour, at the beginning of our era, had eighty thousand inhabitants." (Westphal, Die Römische Kampagne, p. 7.)
[588] The reformation of the Kalendar was effected in B.C. 46. Dion Cassius (43. c. 26) says that Cæsar was instructed on this subject during his residence at Alexandria in Egypt. The Egyptians had a year of 365 days from a very early date (Herodotus, ii. 4). In this year (B.C. 46) Cæsar intercalated two months of 67 days between November and December, and as this was the year in which, according to the old fashion, the intercalary month of 23 days had been inserted in February, the whole intercalation in this year was 90 days. Cæsar made the reformed year consist of 365 days, and he directed one day to be intercalated in every fourth year (quarto quoque anno) in order that the civil year, which began on the 1st of January, might agree with the solar year. The old practice of intercalating a month was of course dropped. The year B.C. 46 was a year of 445 days. By this reformation, says Dion Cassius, all error was avoided except a very small one, and he adds, that to correct the accumulations of this error, it would only be necessary to intercalate one day in 1461 years. But this is a mistake; for in 1460 years there would be an error of nearly eleven days too much. Ten days were actually dropped between the 4th and 15th of October, 1582, by Gregory XIII., with the sanction of the Council of Trent.
A curious mistake was soon made at Rome by the Pontifices who had the regulation of the Kalendar. The rule was to intercalate a day in every fourth year (quarto quoque anno). Now such expressions are ambiguous in Latin, as is shown by numerous examples. (Savigny, System des heut. Röm. Rechts, iv. 329.) The expression might mean that both the year one and the year four were to be included in the interpretation of this rule; and the Pontifices interpreted it accordingly. Thus, after intercalating in year one, they intercalated again in year four, instead of in year five. In the time of Augustus, B.C. 8. the error was corrected, and the civil year was set right by dropping the three intercalary days which came next after that year, three being the number of days in excess that had been intercalated. For the future the rule of Cæsar was correctly interpreted. Dion Cassius in expressing the rule as to intercalation uses the phrase, διὰ πέντε ἐτῶν.
The subject of Cæsar's reformation is explained in the notes to Dion Cassius (43. c. 26), ed. Reimarus, and in the article Calendar (Dictionary of Greek and Roman Antiquities) by Professor Key.