Historical clue formulations

• Object of knightly quests — 2024-12-22
• Coveted cup — 2023-11-09
• Something highly sought after — 2023-08-17
• Last Supper item — 2019-11-10
• Holy ___ — 2019-01-31
• See 22-Across — 2015-07-25
• Quest in a Monty Python movie — 2013-03-04
• Percival caught sight of it — 2010-01-09
• Sacred cup — 2008-03-16
• Object of a knight's quest — 2007-08-02
• Holy ___ — 2004-09-22
• Last Supper item — 2004-09-05
• Object of many knightly quests — 2001-04-04
• Last Supper cup — 2000-06-27
• Holy chalice of legend — 1997-08-05
• Ultimate object — 1996-09-19