Arachidamia (Greek: Αραχιδάμεια) (c. 340-241 BC) was a wealthy Spartan queen, wife of Eudamidas I, mother of Archidamus IV and Agesistrata, grandmother of Eudamidas II, great-grandmother and grandmother of Agis IV.
The earliest accounts of her depict her leading Spartan women against Pyrrhus during his siege of Lacedaemon in the 3rd century BC. In the face of Pyrrhus's invasion, the Spartan Gerousia considered sending the Spartan women to Crete for their safety. Arachidamia, speaking on behalf of the Spartan women, entered the Gerousia, "with sword in hand," and contested this proposal, questioning whether the Spartan women were expected to survive the ruin of their own city.
With the matter settled, the Spartans initiated the construction of a defensive trench running parallel to Pyrrhus's camp. It is likely that Arachidamia helped direct the Spartan women in this respect, since it is reported that the Spartan women impressively "completed with their own hands a third of the trench." Consequently, it is likely that Arachidamia led the efforts of Spartan women during the subsequent battle against Pyrrhus, as they are noted for supplying the defenders with weapons and refreshment during combat, and extracting wounded from the battlefield.
Later records of Arachidamia date three decades later, with her assisting in the revolutionary designs of her grandson Agis IV, as he attempted to restore Lycurgan institutions to a Sparta then thoroughly corrupted by wealth and greed. Because Arachidamia and Agesistrata were the wealthiest two people in all of Lacedaemon, Arachidamia's support of Agis was instrumental in gaining support for the cause. She was among those who first pledged to contribute their wealth to a common pool, which was then to be distributed equally amongst both old and new Spartan citizens.
However, these revolutionary designs were foiled by the corruption of Agis's uncle and erstwhile supporter, Agesilaus, and the machinations of a rival party, led by the Agiad King, Leonidas II. Leonidas and the Ephors had Agis illegally imprisoned and executed, unbeknownst to a mob that had gathered out of concern and a possible desire to see him freed. Arachidamia and Agesistrata were subsequently lured into the prison on the premise that they were to see Agis; and there they too both met their ends at the hands of their political rivals. Considering that she must have born her son Archidamus IV before 320 BC, at the time of her execution in 241 BC she was probably far in her nineties.
- Eudamidas II was wedded to Agesistrata, his aunt.
- Hodkinson, Stephen (1986). Land Tenure and Inheritance in Classical Sparta. The Classical Quarterly, New Series, Vol. 36, No. 2 (1986). Cambridge University Press. pp. 378–406.
- Plutarch, Parallel Lives: Life of Pyrrhus § 27.2
- Salmonson, Jessica Amanda (1991). The Encyclopedia of Amazons. Paragon House. p. 17. ISBN 1-55778-420-5.
- Plutarch, Parallel Lives: Life of Pyrrhus § 27.3
- Plutarch, Parallel Lives: Life of Pyrrhus § 27.4
- Plutarch, Parallel Lives: Life of Pyrrhus § 29.3
- Plutarch, Parallel Lives: Life of Agis § 7.1-7.3
- Plutarch, Parallel Lives: Life of Agis § 4.1
- Plutarch, Parallel Lives: Life of Agis § 7.3
- Plutarch, Parallel Lives: Life of Agis § 8.1-8.2; 9.3
- Plutarch, Parallel Lives: Life of Agis § 13.4; 16.1-16.2
- Plutarch, Parallel Lives: Life of Agis §18.2-18.4
- Plutarch, Parallel Lives: Life of Agis § 19.3; 20.1
- Plutarch, Parallel Lives: Life of Agis § 20.2-20.5