You can unlock the items listed below by successfully collecting the corresponding number of hidden feathers:

• Condottiero War Hammer (50) - You can find the Condottiero War Hammer at the blacksmith's shop in the Villa Monteriggioni once you have collected 50 hidden feathers.
• Auditore Cape (100) - Mario will award the Auditore Cape to you when you go to the Villa Monteriggioni and talk to him after collecting a 100 hidden feathers.

Preempt getting a Notorious rating by bribing Herald prior to getting it. To get your money back, simply steal it back from him after you have bribed him.