Historical clue formulations

• Lowest number not found on a grandfather clock — 2019-03-06
• Number of one of the Olympics canceled due to W.W. II — 2011-12-31
• Unlucky number for Caesar? — 2011-09-28
• Chapter 13? — 2008-12-26
• Number not on a grandfather clock — 2004-05-03
• Hour not found on a grandfather clock — 1999-08-16
• Constitutional Amendment that abolished slavery — 1999-03-30
• Number not on a clock — 1996-12-20
• Missing floor in Caesar's Palace? — 1995-08-25