Possible Clues:

• A greeting
• Before start of Thermopylae the whole Greek city cheers
• The ballets rewritten for well-wishers at the end of message
• Parting words for the elite
• Well-wisher's signoff
• Well-wisher's wish
• Beginning to lose in battle, he's desperate for good luck!
• Good luck, lock's opening ancient city secured by key
• Cheers those in heaven presumably
• Cheers a military officer seizing large city of old