Akanthos (Ancient Greek: Ἄκανθος; Latin: Acanthus) was an ancient Greek city on the Athos peninsula, on the narrow neck of land between the sacred mountain and the mainland, to the northwest of the Xerxes Canal. It was founded in the 7th century BCE as a colony of Andros, itself a colony of Chalcis in Euboea. Chalcidice was multi-cultural. The archaeology of the region suggests that some Hellenes were already there. The site is on the north-east side of Akti, on the most eastern peninsula of Chalcidice.

The ancient city extended along a ridge comprising three hills bordering the south-east of modern Ierissos about 0.6 km (2,000 ft) from it. The ridge dominates the landscape. It is terminated on the north by the coastal road (Vasileos Konstantinou) and the beach between Ierissos and its harbor. The modern city is about equal in size to the ancient site, which is now partially wooded. Remains of an 8 m (26 ft) high circuit wall, a citadel, and Hellenistic buildings are visible embedded in the terrain, along with a deserted Byzantine church and two post Byzantine churches.

The name selected for the colony is a phytoname, the name of a plant. The plant would most likely be Acanthus mollis, which abounds on the Mediterranean rocky coasts. Pomponius Mela says that it grew on the coast between the River Strymon and Athos. The plant, a thorny, flowering perennial, was known for its medicinal powers. It is the model for the plant design used on Corinthian capitals.

The prosperous and successful city in the course of time became a part of the Byzantine Empire. In the 6th century CE the empire declined due to devastation of its population by plague, starting about 541. The peninsula was abandoned by the Hellenes only to be gradually repopulated by Slavs. In the 9th century the Byzantines recovered and reoccupied the peninsula, bringing in Hellenes and Armenians from Asia Minor. They were protected in Roman-style fortified towns called kastra. One of these was Erissos, placed over the site of Akanthos. After it became the site of a Bishopric, Erissos was changed to Ierissos by analogy with Hieros, "sacred."

There is an etymology for Erissos as follows. The Marble of Ladiava, an inscription from Ierissos, reports the presence of a large community of Roman merchants, 27 BCE–14 CE. They chose to call Akanthos, etymologically "spiny," Echinia, "hedgehog." In the course of time Echinia came to mean "sea urchin," which also is spiny. The Roman colony disappeared along with the Greek city in the 6th century. When the Byzantines returned they chose the Latin form of the word, Ericius, which became Erissos by palatalization of the "c."

In 1430 Thessaloniki fell to Murad II, bringing Macedonia finally under the Ottoman Empire. Before then it had changed hands among the Ottomans, the Byzantines, and the Republic of Venice, since the late 14th century. The native population fleeing the city were pursued and brought back by the Turkish army. Subsequently, the city was augmented by the forced transplantation of Yuruk tribesmen from Anatolia, semi-nomads who kept sheep, practicing transhumance over the grasslands of Halkidiki, The region had been gradually deforested during the Byzantine era. The Ottoman rulers left Halkidiki in the hands of the monastic communities of Athos, whom they encouraged and allowed to rule.

Despite vigorous revolutionary activity in the Greek War of Independence of 1821, Macedonia, of which Halkidiki was a part, was forced to remain under the empire. In 1912 the Kingdom of Greece combined with other Balkan states to liberate Macedonia from Ottoman rule in the Balkan Wars. Macedonia was then divided among the victors, Greece receiving south Macedonia, with Thessaloniki and Halkidiki. In 1922 the Turkish people abolished the empire in favor of the Turkish Republic. In the 1923 population exchange consequent on the border settlement with Greece, Ierissos received an influx of Anatolian Greeks.

In 1932 a major earthquake devastated the village beyond re-use. It became "old Ierissos" as opposed to "new Ierissos" subsequently constructed in the valley below the hill. Unknown to the builders, the valley floor is the site of an ancient cemetery in use since before the founding of Akanthos, not abandoned until the 17th century CE. The new Ierissos is a flourishing city, architecturally in the style of the 1930s. The municipal arrangements of modern Greece have changed a number of times since then. More recently, the fact that Stagira, named for ancient Stagira, is in the vicinity stimulated the creation of the municipality, Stagira-Akanthos. In 2011 the name was changed to Aristotelis in honor of the Stagirite philosopher, Aristotle.