ante diem xviii kalendas januarias

• Consualia — a festival in honour of Consus which likely involved a similar celebration held on August 21 (i.e. horse races, chariot races, and garlanding of the steeds)
• 337 B.C. — death of Timoleon (according to one reckoning)
• 215 B.C. — assassination of Hieronymus, one of the tyrants of Syracuse (by one reckoning)
• 19 B.C. — dedication of the Ara Fortunae Reducis
• 37 A.D. — birth of the future emperor Nero
• 130 A.D. — birth of the future co-emperor Lucius Verus

ante diem xix kalendas januarias

• 250 A.D. — martyrdom of Heron
• 283 A.D. — martyrdom of Justus and Abundius

idus decembres

• Rites in honour of Tellus, the earth goddess which perhaps included a lectisternium (a ‘dinner party’ at which images of the god(s) would ‘dine’ with participants) in honour of Ceres.
• 405 B.C. — battle of Aegospotami (by one reckoning)
• 304 A.D. — martyrdom of Lucy of Syracuse
• 1783 — Death of Samuel Johnson

We might also note here something mentioned in Josephus (Ant. 14.8), which he places in the year 46 (I believe):

When Antipater had made this speech, Caesar appointed Hyrcanus to be high priest, and gave Antipater what principality he himself should choose, leaving the determination to himself; so he made him procurator of Judea. He also gave Hyrcanus leave to raise up the walls of his own city, upon his asking that favor of him, for they had been demolished by Pompey. And this grant he sent to the consuls to Rome, to be engraven in the capitol. The decree of the senate was this that follows: (13) “Lucius Valerius, the son of Lucius the praetor, referred this to the senate, upon the Ides of December, in the temple of Concord. There were present at the writing of this decree Lucius Coponius, the son of Lucius of the Colline tribe, and Papirius of the Quirine tribe, concerning the affairs which Alexander, the son of Jason, and Numenius, the son of Antiochus, and Alexander, the son of Dositheus, ambassadors of the Jews, good and worthy men, proposed, who came to renew that league of goodwill and friendship with the Romans which was in being before. They also brought a shield of gold, as a mark of confederacy, valued at fifty thousand pieces of gold; and desired that letters might be given them, directed both to the free cities and to the kings, that their country and their havens might be at peace, and that no one among them might receive any injury. It therefore pleased [the senate] to make a league of friendship and good-will with them, and to bestow on them whatsoever they stood in need of, and to accept of the shield which was brought by them. This was done in the ninth year of Hyrcanus the high priest and ethnarch, in the month Panemus.”

That little 13 there refers to a note in the Whiston edition of Josephus at the CCEL … here’s the skinny:

Take Dr. Hudson’s note upon this place, which I suppose to be the truth: “Here is some mistake in Josephus; for when he had promised us a decree for the restoration of Jerusalem he brings in a decree of far greater antiquity, and that a league of friendship and union only. One may easily believe that Josephus gave order for one thing, and his amanuensis performed another, by transposing decrees that concerned the Hyrcani, and as deluded by the sameness of their names; for that belongs to the first high priest of this name, [John Hyrcanus,] which Josephus here ascribes to one that lived later [Hyrcanus, the son of Alexander Janneus]. However, the decree which he proposes to set down follows a little lower, in the collection of Raman decrees that concerned the Jews and is that dated when Caesar was consul the fifth time.” See ch. 10. sect. 5.