Two years later in 422 BC, a new Athenian force under the general Cleon failed once more during the Battle of Amphipolis at which both Kleon and Brasidas lost their lives.

The city itself kept its independence until the reign of king Philip II (r. 359 – 336 BC) despite several Athenian attacks, notably because of the government of Callistratus of Aphidnae.

In 357 BC, Philip succeeded where the Athenians had failed and conquered the city, thereby removing the obstacle which Amphipolis presented to Macedonian control over Thrace.

Apart from the ramparts of the lower town, the gymnasium and a set of well-preserved frescoes from a wealthy villa are the only artifacts from this period that remain visible.

Though little is known of the layout of the town, modern knowledge of its institutions is in considerably better shape thanks to a rich epigraphic documentation, including a military ordinance of Philip V and an ephebarchic law from the gymnasium.

[15] After the final victory of Rome over Macedonia in the Battle of Pydna in 168 BC, Amphipolis became the capital of one of the four mini-republics, or merides, which were created by the Romans out of the kingdom of the Antigonids which succeeded Alexander's empire in Macedon.

During the period of Late Antiquity, Amphipolis benefited from the increasing economic prosperity of Macedonia, as is evidenced by the large number of Christian churches that were built.

This has been taken as evidence that the large fortified perimeter of the ancient town was no longer defendable, and that the population of the city had considerably diminished.

One possible explanation provided by the historian André Boulanger is that an increasing ‘willingness’ on the part of the wealthy upper classes in the late Roman period to spend money on local gentrification projects (which he terms euergetism, from the Greek verb εὐεργετέω; meaning 'I do good') was exploited by the local church to its advantage, which led to a mass gentrification of the urban centre and of the agricultural riches of the city's territory.

[17] The Slavic invasions of the late 6th century gradually encroached on the back-country Amphipolitan lifestyle and led to the decline of the town, during which period its inhabitants retreated to the area around the acropolis.

Its inhabitants probably moved to the neighbouring site of ancient Eion, port of Amphipolis, which had been rebuilt and refortified in the Byzantine period under the name “Chrysopolis”.

The last recorded sign of activity in the region of Amphipolis was the construction of a fortified tower to the north in 1367 by the megas primikerios John and the stratopedarches Alexios to protect the land that they had given to the monastery of Pantokrator on Mount Athos.

The Greek Archaeological Society under D. Lazaridis excavated in 1972 and 1985, uncovering a necropolis, the city wall (see photograph), the basilicas, and the acropolis.

Parts of the lion monument and tombs were discovered during World War I by Bulgarian and British troops whilst digging trenches in the area.

[18] The silver ossuary containing the cremated remains of Brasidas[19] and a gold crown (see image) was found in a tomb in pride of place under the Agora.

In 2012[20] Greek archaeologists unearthed a large tomb within the Kasta Hill, the biggest burial mound in Greece, northeast of Amphipolis.

The large size and quality of the tumulus indicates the prominence of the burials made there, and its dating and the connections of the city with Alexander the Great suggest important occupants.

The ancient bridge that crossed the river Strymon was mentioned by Thucydides,[24] was strategic as it controlled access between Macedonia and the Chalkidike in the west to Thrace in the east, and was important for the economy and trade.

The stone stela bearing the rules of the gymnasium was found in the north wing, detailing the duties and powers of the master and the education of the athletes.

After it was destroyed in the 1st c. BC in the Thracian rebellion against Roman rule, it was rebuilt in Augustus's time in the 1st c. AD along with the rest of the city.