Historical clue formulations

• Aspire — 2021-04-17
• Take pains — 2011-09-24
• Undertaking — 2003-10-07
• Enterprise — 2001-06-24
• Do one's darnedest — 1999-06-26
• Attempt — 1999-05-16
• Undertaking — 1996-05-19
• Attempt — 1995-09-04