Athens Sights - Hadrian's Arch
Ostensibly the arch separated the original classical section of Athens from the new construction inaugurated by Hadrian of the Roman quarter, although these boundaries are hard to define.
There is an inscription to this effect on the arch itself comparing Hadrian's Athens to the Athens of Theseus, the cities legendary founder. Hadrian was Grecophile. He liked Greece and spent a lot of money on public works which is why the Greeks of today still revere and respect him and even have a quite a large street named after him in the Plaka called Adrianou.