Possible Clues:

• Verse to aid memory
• 'Thirty days hath September ...,' e.g
• “Richard of York gave battle in vain”, for example
• Trigger for the memory
• Clue not to be forgotten
• It may help to recall -- with rise of Medici, no men missed taking part
• As jogger, sides of mountain come in for pounding
• Aide-memoire
• Name in note, name I initially chronicled as a reminder
• A typical one for the 35-Across can be found in the first words of the answers to starred clues