The rocky peninsular of the Acronauplia comprised the walled settlement of Nauplion from ancient times until the end of the 15th century.

The Acronauplia walls bear witness to its rich history, which it must be confessed, is a little difficult to follow, due to its long uninterrupted inhabitation. The current form of the castle, although quite changed by modern intervention, basically crystallised during the Frankish and first Venetian occupations from the 13th to 16th centuries.

Evidence of a pre-historic settlement has been found, and on the west side, a section of the ancient polygonal walls from the 4th century BC has survived. There are also remains of the walls from the Hellenistic and Byzantine periods.