Historical clue formulations

• "Enthusiasm is the mother of ___": Ralph Waldo Emerson — 2023-12-27
• Try — 2018-05-23
• Exercitation — 2017-03-12
• What to get an "E" for — 2016-08-15
• What an E may stand for — 2010-10-25
• Pains — 2006-01-22
• Physical exertion — 2006-01-11
• Push — 2005-08-11
• Attempt — 2005-07-19
• Struggle — 2000-09-24
• Industry — 2000-05-14
• Attempt — 1998-02-21
• Application — 1997-02-16
• Diligence — 1995-11-08