Possible Clues:

• Evoking Camelot
• Of a legendary king and his Knights of the Round Table
• Like legends in which alien gets tip-off about Ben?
• Like some legends concerning heretic badly hurt when imprisoned
• Of a legendary king
• Royal heretic is about much of the day
• Part of opera — about twelve hours? — with name of legendary hero
• In days of knights?
• Sort of legend from day one presented in woolly fashion
• Relating to the once and future king