Historical clue formulations

• Running portion of an Ironman race — 2022-09-26
• 1976 Dustin Hoffman thriller — 2016-05-12
• *26-mile race — 2015-06-08
• Long-running event? — 2015-05-24
• Part of an Ironman competition — 2010-01-24
• Lasting event? — 1999-07-09
• Unusually long — 1998-11-08
• Part of an ironman competition — 1997-10-16
• Battle site where the Athenians routed the Persians — 1997-04-15
• 490 B.C. battle site — 1996-01-30
• Endurance contest — 1995-10-18