After upgrading the spear of Leonidas in the temple on Andros, it is time to make your way to Athens. Board your ship and sail south west to the Heights of Thorikos. As you sail be cautious of any pirate ships along the way; these are dangerous waters and some of the pirates that you encounter may far out level you. It is best to use Ikaros to identify the level of an opponent before considering an attack. If they are more than five levels above you, it is probably wise to avoid combat.
When you approach the shoreline a brief cut scene will initiate, in which Herodotus requests that you meet him at the Pynx in Athens when you are ready. You can now take the time to explore or complete any number of side quests within the region, but it is not necessary if you would rather immediately progress with the story. Either way, when you are ready mount your horse and make your way to Athens. As you approach the city, head for the north east entrance and use Ikaros to scout the region to identify any important locations.
You will find Herodotus at the Pynx. When you approach it a cut scene will initiate, after which you should go with Herodotus to Perikles. Speak with him about what he requires from you, it does not matter which options you choose. You will be assigned three new quests and this one will complete.