Kyniska was the sister of Agis II and
Agesilaos II (king of Sparta from ca. 398-360 BC). The latter persuaded her to breed chariot horses and participate in the Olympic games (Xenophon; Plutarch). She was actually the first woman to do so and win an Olympic victory (Paus. 3.8.1).
Pausanias saw two victory monuments of Kyniska (5.12.5, 6.1.6). One consisted of bronze horses, the other of a chariot, horses, a charioteer and a statue of Kyniska herself. The base of both the first (possibly IvO 634) and the second (IvO 160 = IG V/1, 1564a = IAG 17) have been found. Both of them were works by Apellas, son of Kallikles.
An estimated date may be the early 4th century BC, based on her brother's rule and the active period of Apellas. Moretti 1957, nos. 373, 381 suggests the 96th Olympiad (= 396 BC) and the 97th Olympiad (= 392 BC).