Historical clue formulations

• Nerves of steel, e.g. — 2019-05-13
• Something that shouldn't be mixed — 2018-09-23
• Sand in an hourglass, for time — 2013-05-29
• "A mighty fortress is our God," e.g. — 2001-01-21
• "Life is a bowl of cherries," e.g. — 1995-01-24