Historical clue formulations

• Start of a secret invitation, perhaps — 2026-01-16
• Start of a rendezvous request — 2021-09-26
• "Let's get together" — 2012-05-03
• What to do "in St. Louis," in an old song — 2011-12-19
• Start of a tryster's message — 2003-04-27
• Start of a lover's request — 2000-12-30
• What to do "in St. Louis" — 1997-12-28