Historical clue formulations

• Final movement of Beethoven's Ninth — 2023-04-17
• Anthem of the European Union — 2021-01-09
• Schiller work adapted by Beethoven — 2017-08-23
• Schiller work set to music by Beethoven — 2016-03-25
• European Union anthem — 2015-03-07
• Highlight of Beethoven's Ninth — 2014-12-11
• Work by 16-Across — 2011-03-15
• Highlight of Beethoven's Ninth Symphony — 2006-11-30
• Classic song that's the official anthem of the European Union — 2006-05-20
• Schiller poem used by Beethoven — 2004-05-28
• Schiller work adapted by Beethoven — 2001-12-16