In mainland Greece, the construction was often a federal state consisting of several individual poleis (city-states) with shared political institutions and citizenship. Examples of this are the Achaean League and the Aetolian League.
In Asia Minor, the term was also used for the political merger of two or more neighboring poleis, which could eventually, but not necessarily, lead to the disappearance of one of the participating poleis.
A League typically shared functions such as defense, diplomacy, economics, and religious practices among its member states.

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Reverse: fish under (AX) monogram all within wreath; (APT) left / ΔY up
Die Orientation: -
Weight: 2.2 g

Reverse: (AX) monogram, thunderbolt below, all within wreath; ΞB / K_A / M
Die Orientation: -
Weight: 2.4 g

Reverse: (AX) monogram within wreath; A_N / CΩ
Die Orientation: -
Weight: 2.4 g

Reverse: lyre above (AX) monogram, all within wreath; ΔΩ_PO
Die Orientation: -
Weight: 2.3 g

Reverse: (AX) monogram, trident below, all within wreath; A / Π_Λ / (YE)
Die Orientation: -
Weight: 2 g
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Reverse: Poseidon standing left, holding trident
Die Orientation: 6 H
Weight: 3.98 g

Reverse: BOIWTWN (upward on left), ornamented trident head upward, straight crossbar, dolphin upward on right, no control symbol
Die Orientation: 0 H
Weight: 1.92 g

Reverse: BOIWTWN (upward on left), ornamented trident head upward, straight crossbar, dolphin upward on right, no control symbol
Die Orientation: 0 H
Weight: 2.1 g

Reverse: Eagle standing left on lightning, cornucopia right, star above; BPET_TIΩN
Die Orientation: -
Weight: 7.3 g
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Reverse: BP - ETTIΩN / Helmeted, naked warrior charging r. holding shield and spear; below shield, torch
Die Orientation: -
Weight: 8.14 g

Reverse: Quadripartite incuse square with alternating raised and sunken quarters; pellet in one sunken quarter, wreath in the opposite
Die Orientation: -
Weight: 2.09 g

Reverse: quatripartite incuse square, grain ear in one section, X· in other
Die Orientation: -
Weight: 2.25 g

Reverse: Tripod in wreath, AΠEI-PΩTAN on either side
Die Orientation: 0 H
Weight: 25 g

Reverse: head of Artemis right; Φ O K I
Die Orientation: -
Weight: 2.9 g

Reverse: laureate wreath; T
Die Orientation: -
Weight: 8.9 g

Reverse: Athena Itonia right throwing spear holding shield; ΘEΣΣA / ΛΩN, ΦIΛOK, A / Σ _ OP, (ΓA)
Die Orientation: -
Weight: 6.68 g

Reverse: Athena Itonia advancing right; [Δ]IO-KΛHΣ above spear, N-I in inner fields
Die Orientation: -
Weight: 6.26 g
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Reverse: Athena Itonia right; Π-I across central field
Die Orientation: 7 H
Weight: 4.14 g

Reverse: Athena Itonia advancing right holding spear and shield; ΘEΣΣA_ΛΩN
Die Orientation: -
Weight: 3.6 g