The preservation of this temple is utterly incredible. Not only is it the best preserved Greek Agora building, but it is the only temple in the whole of Greece that retains its roof. After travelling through Greece and finding a great deal of charm but a lot of ruins, it is a real pleasure for visitors to find a building still standing. 

It is believed to have been built between 449 and 440 BC, but in 415 BC some minor refinements were made. The building's architect is unknown, although some attribute it to Ictinus, who was also responsible for constructing the Parthenon. The Temple of Hephaestus was the starting point for the ambitious project of Pericles, who wanted to restore the splendour of Greece after his victory over the Persians. 

Dominating the western part of the Agora, on Kolonos Hill, the Temple of Hephaestus was devoted to the god Hephaestus, of course, and the goddess Athena, whose bronze sculptures stood in the central part of the building. This was understandable, since the temple was located in a neighbourhood of blacksmiths and craftsmen, where there were also stalls selling ceramics. Athena and Hephaestus were the patrons of these two professions, respectively. 

The temple was also known as the Theseion, a name by which it is still known today. This is because, at the time, it was believed that the remains of the mythical hero Theseus were buried in the temple. The truth is, however, no one knows where his grave is, although this name for the temple has stuck. 

The Hephaestion was constructed in Pentelic marble, as were most of the buildings of the time. It is a Doric temple surrounded by columns, and has pronaos and episthodomos, porticos with columns that were at the front and rear of the shrine, respectively. These porticos were decorated with Ionic friezes depicting scenes of the struggles of Theseus and the Centauromachy, although the severe deterioration makes some of them difficult to decipher. 

Of the temple's 68 metopes, only 18 were carved, and it is believed that the remaining 50 were painted, although no traces of these remain.

You will be surprised to learn that there were trees planted in a series of holes arranged around the temple in the 3rd century BC. This has led experts to deduce that the landscape was entirely planned, and that there was a garden, or at least an organised series of vegetation, outside the building. 

In the 7th century AD, the temple was converted into a Christian church dedicated to St George and, more than 10 centuries later, it was also a cemetery. In the 19th century, King Otto was crowned in the temple, and he subsequently turned it into a museum.

Today, the Hephaestion, or Theseion, is undoubtedly one of the main attractions of the archaeological site of the ancient Agora. Its remarkable degree of preservation does not require you to use your imagination quite so much, since you do not have to try to picture what the building was like. And you cannot fail to be impressed.