Possible Clues:

• Venice-born Polo
• Name that anagrams to "carom"
• Shout before "Polo!"
• Silk Road explorer Polo
• Old traveller in company car with damage in front
• Shout answered with 'Polo!'
• Call followed by 'Polo!'
• __ Antonio (Caesar's ''compadre'')
• ___ Polo (messaging app)
• **Call before "Polo!" (4 and 5)