The Romans had their dies fasti, corresponding to the modern court days in England. On such days, of which there were thirty-eight in the year, it was lawful for the praetor to administer justice and to pronounce the three words, Do, dico, addico, "I give laws, declare right, and adjudge losses."
The days on which the courts were not held were called nefasti (from ne and fari), because the three words could not then be legally spoken by the praetor. But these days came to be regarded as unlucky, a fact rendered evident by an expression of Horace. The Romans also classed as unfortunate the days immediately following the calends, nones, and ides of each month. Unlucky days were termed dies atri, because they were marked in the calendar with black charcoal, the lucky ones being indicated by means of white chalk. There were also days which were thought especially favorable for martial operations, but the anniversary of a national misfortune was considered very inauspicious. Thus after the defeat of the Romans by the Gauls under Brennus on the banks of the river Allia, July 16, 390 B. C., that date was given a prominent place among the black days of the calendar. But not every general was influenced by such superstitions. Lucullus, when an attempt was made to dissuade him from attacking Tigranes, king of Armenia (whom he defeated B. C. 69), because upon that date the Cimbri had vanquished a Roman army, replied, "I will make it a day of good omen for the Romans." The Roman ladies, we are told, gave less heed to the unlucky days of their own calendar than to the works of Egyptian astrologers, among whom Petosiris was their favorite authority, when they wished to ascertain the proper day, and even the hour, for the performance of household and other duties.
Horace (book ii. ode xiii.) thus apostrophizes a tree, by whose fall he narrowly escaped being crushed at Sabinum: "Thou cursed tree! whoever he was that first planted thee did it surely on an unlucky day, and with a sacrilegious hand."
The Latin writer, Macrobius, stated that when one of the nundinoe or market days fell upon New Year's, it was considered very unfortunate. In such an event the Emperor Augustus, who was very superstitious, adopted the method of inserting an extra day in the previous year and subtracting one from that ensuing, thus preserving the regularity of the Julian style of reckoning time. Ordinarily, however, New Year's Day was deemed auspicious, and on that day, as now, people were accustomed to wish each other happiness and good fortune.