Historical clue formulations

• Opposite of day, in Germany — 2023-09-12
• "Gute ___" (German bedtime words) — 2017-01-11
• When to see der Mond — 2012-05-12
• After-dark time in Germany — 2011-05-31
• When it's dark, in Darmstadt — 2000-04-21
• "Stille ___" (Christmas carol) — 1999-01-03
• Strauss's "Eine _____in Venedig" — 1993-12-10