You take them back to the Tree of Immortality, where Athena will show you a secret message on the items.
At his realm that is in the Gates.
Continue finding the 5 sacred items.
You need the 5 sacred items to defeat Zeus and the island to get the medallion
They are listed on the scroll you receive from Zeus.
Once you have all 5 of the sacred items, return to the Tree of Immortality, where Athena will help you arrange the hidden message on the items. Zeus will appear and take the items, and you can then go to Hercules to ask for his help.
Collect the rest of the 5 sacred items and return them to the Tree of Immortality.
Head back to the tree of immortality and talk to Athena.
Your quest on Mythology Island is to give Zeus the 5 items;the rose, the whisker, the scale, the pearl, and the golden ring. To do this, you have to get the apple (to summon Zeus and then actually get the quest).
Go talk to Athena.
She is at the Tree of Immortality. You must see her before you can access the throne rooms of Poseidon or Hades.
The whisker from Cerberus is one of the Five Sacred Items sought by Zeus. When you have all 5 listed on the Scroll, return to the Tree of Immortality with them.
When you have all 5 items, take them back to the Tree of Immortality and Athena will help you decode the message hidden on them. When you finish, Zeus will come and take them from you, without honoring his promise.