The McDonald Institute and this journal have adopted as their logo a three-legged symbol, with wings on each heel, known in Graeco-Roman antiquity as the triskeles. The purpose of this article is to explore the meaning of the iconography of this emblem, and to investigate how and why it came to symbolize the islands of both Man and Sicily. It is suggested that the Isle of Man adopted the triskeles in 1266 when the control of the island passed from the Norse kings to Alexander III of Scotland; a possible connection with Sicily is tentatively explored. The Man triskeles is clothed in leg armour, however, and has spurs, not wings, on the ankles. In Sicily the triskeles is first attested in the seventh century BC and was gradually elaborated from the later fourth century BC onwards, first with the addition of wings to the feet, then with the use of a Medusa head at the centre, and finally with the adjunct of three barley ears to symbolize the agricultural fertility of the island. Widely adopted also on coinage in Athens and Asia Minor from the sixth century BC, the triskeles was probably in origin a sun symbol like the swastika.