Historical clue formulations

• Sent by post — 2026-05-18
• On its way, in a way — 2025-08-07
• Took to the post office — 2017-08-07
• Sent — 2011-06-01
• Posted — 2004-02-24
• Like many packages — 2000-07-01
• Sent in — 1999-08-24