Historical clue formulations

• Memorable part of Rossini's "William Tell" — 2023-11-05
• William Tell was given one — 2020-06-19
• Oratorio opener, often — 2019-02-22
• *First track on many a Broadway album — 2009-12-10
• Famous part of Rossini's "William Tell" — 2008-12-01
• Orchestral intro — 2007-02-19
• Introductory offer — 1994-10-30