It was constructed in 132 A.D  by the Atheneans  in honour of the Roman emperor Hadrian. It’s a combination of Greek and Roman architecture made of marble. It is 18 meters high and it was the boundary between the ancient city of Athens (city of Theseus) and the roman city (city of Hadrian). In 1778 the arch was incorporated in the eastern part of the Ottoman wall of the city. It was at that time when it was converted into a gate, known as the Princess Gate.