Theseus is the main super hero of Athenian myth and the chap credited with uniting the disparate villages of Attika. In gratitude Theseus (like Lord Byron's Vyronas) gets a whole section of town named after him called Thession.
Theseus also gets his moniker on the beautiful near by temple, called, by most local people, the Thession. Its the best preserved temple in Greece too by the way and in the Athenian Agora. We call it the Athenian agora to distinguish it from the Roman Agora. And most folks call the temple the Thession but some people, archeologists mostly, also call it the temple of Hephaisteos (Vulcan) and they do this because Hephaisteos was not only married to Aphrodite (the goddess of love) but was also the patron God of metal smiths who had their workshops right near by.
So the name of the Temple is either Hephaisteos or Theseus depending on which archeologist is in fashion at the moment. In order to see the temple from Thession you can enter the Athenian Agora, which is quite large, from several entrances, one of which is just by the Thession Metro Station! If you walked through the Agora you could come out in Monastiraki Sq and save yourselves some hiking in the hot sun.
Thession Page Two