Julius Caesar may have had his terrible horrible no-good very-bad day on the 15th of March (at least according to Shakespeare), but today, the 15th of August, was doomsday for two other rulers who inspired the Bard. The Scottish king Duncan died today in 1040, and the guy who took over for him died today in 1057. You may have heard of him; his name's Macbeth.

Eerie, right? Although things didn't happen in "out, damn spot" fashion, it's entirely possible that the historical Macbeth (or as he was then known Mac Bethad) really did kill Duncan (or as he was then known Donnchad). Duncan, a young and feisty fellow, was in the habit of leading disastrous military expeditions. In 1040 he marched into what was traditionally viewed as Macbeth's territory in Morayshire. Macbeth, who was in charge of Duncan's army, seems to have turned the men against the king and killed him, though in battle, not in his sleep a la Shakespeare.

No matter how accurate the famous play is, however, there was definitely some poetic justice in real life. When Macbeth died exactly 17 years after killing Duncan, it was at the hands of the future Malcolm III of Scotland -- Duncan's son.

By the way, the Ides of August was actually on Sunday, not today. The Roman calendar organized its months around three days, each of which served as a reference point for counting the other days:

  • Kalends (1st day of the month)
  • Nones (the 7th day in March, May, July, and October; the 5th in the other months)
  • Ides (the 15th day in March, May, July, and October; the 13th in the other months)

The other days were identified by counting backward from the Kalends, Nones, or the Ides.