Attalis (Ancient Greek: Ἀτταλίς) was a tribe (phyle) added by the ancient Athenians to the previous list of 11 Athenian tribes in the spring of 200 B.C.
[1] just a few months after the "Macedonian" tribes Antigonis and Demetrias were dissolved.
[2] The tribe was named after Attalos I, King of Pergamon, on occasion of his visit to Athens.
[3] The Monument of the Eponymous Heroes had two statues (of the Macedonian kings Antigonos I and Demetrios I) removed and one, for Attalos, added, starting the so-called Period IV.
The 12 demes that formed Attalis were collected from all 11 existing tribes ("rule-of-one"), with the twelfth, Appolonieis, newly created and named after Apollonis of Cyzicus, wife of Attalos I.