Antigonus III Doson in the context of "Euergetes"

The Antigonid dynasty (/ænˈtɪɡoʊnɪd/; Ancient Greek: Ἀντιγονίδαι) was a Macedonian Greek royal house which ruled the kingdom of Macedon during the Hellenistic period. Founded by Antigonus I Monophthalmus, a general and successor of Alexander the Great, the dynasty first came to power after the Battle of Salamis in 306 BC and ruled much of Hellenistic Greece from 294 until their defeat at the Battle of Pydna in 168 BC (Third Macedonian War), after which Macedon came under the control of the Roman Republic.

The wars of the Diadochi witnessed the fall of the Argead dynasty in Macedon resulting in a power vacuum, which the Antigonid and Antipatrid dynasties sought to occupy. The Antigonid family first rose to power when Demetrius I Poliorcetes, son of Antigonus I, ousted Cassander's governor of Athens in 306 BC giving his father control over a land spanning from the Aegean Sea to the Middle East. Despite the subsequent instability and loss of the Asian territory, the family managed to maintain its power in mainland Greece and the islands, with Antigonus II Gonatas ultimately solidifying Antigonid rule over Hellenistic Macedon –a territory also known as the Antigonid Empire. Antigonus III Doson further expanded Macedonian influence in southern Greece reestablishing the Hellenic Alliance with himself as the president. Under Philip V, Antigonid Macedon first came into conflict with Rome, which had become a decisive power in the eastern Mediterranean. In the second century BC, the last Antigonid king, Perseus, became known as the champion of Greek resistance against Rome, albeit Rome's control over Antigonid Greece began to steadily expand, culminating in the fall of the dynasty in 168.

The Cleomenean War (229/228–222 BC) was fought between Sparta and the Achaean League for the control of the Peloponnese. Under the leadership of king Cleomenes III, Sparta initially had the upper hand, which forced the Achaean League to call for help the Macedonian king Antigonos Doson, who decisively defeated Cleomenes in the battle of Sellasia in 222.

In 235 BC, Cleomenes III (r. 235–222 BC) ascended the throne of Sparta and began a program of reform aimed at restoring traditional Spartan discipline while weakening the influence of the ephors, elected officials who, though sworn to uphold the rule of Sparta's kings, had by the time of Cleomenes come to wield extraordinary political power in the Spartan system. When, in 229 BC, the ephors sent Cleomenes to seize a town on the border with Megalopolis, the Achaeans declared war. Cleomenes responded by ravaging Achaea. At Mount Lycaeum he defeated an army under Aratus of Sicyon, the strategos of the Achaean League, that had been sent to attack Elis, and then routed a second army near Megalopolis.

The Social War, also War of the Allies and the Aetolian War, was fought from 220 BC to 217 BC between the Hellenic League under Philip V of Macedon and the Aetolian League, Sparta and Elis. It was ended with the Peace of Naupactus.

The Battle of Sellasia took place during the summer of 222 BC between Macedon and the Achaean League, led by Antigonus III Doson, and Sparta under the command of King Cleomenes III. The battle was fought at Sellasia on the northern frontier of Laconia and ended in a Macedonian-Achaean victory.

In 229 BC, Cleomenes initiated hostilities against the Achaean League, the dominant power of the Peloponnese. In a series of campaigns, Cleomenes was successful in defeating the Achaeans, making Sparta the main regional power. This prompted the chief figure of the Achaean League, Aratus of Sicyon, to approach the King of Macedon, Antigonus III Doson, for military assistance. The Macedonians acquiesced on the terms that the Achaean surrender the formidable fortress of Acrocorinth to them. The Macedonians invaded the Peloponnese in 224 BC at the head of a Greek alliance and by 222 BC managed to hem Cleomenes in Laconia.