Possible Clues:

• Assume ten love being held by rather a chivalrous character
• Classic character whose exploits inspired the phrase in this puzzle's circles
• Novel character sporting tuxedo on QI
• Whence the expression 'mum's the word'
• 1869 Minkus ballet
• Idealistic sort
• Ballet based on a 1605 novel, by George
• Classic saga from which the expressions at 23-, 29-, 63-, 83-, 100-, 111- and 114-Across all originated
• Novel finished about bovine going back into desert
• Nine mentioned in citation by professor knight