Mopsus's fame as a seer spread so far that when the Trojan War ended, Calchas, the most famous diviner of the Achaeans, resolved to contend with him. By one account, on his way home he was caught in a storm and cast onto the Asian shore at Colophon; from there he walked on foot up to Klaros.
The riddle that Strabo relates on the authority of Hesiod is simple yet divine. Calchas asks the number of figs on a wild fig tree. Mopsus's answer is flawless: 'Ten thousand; they fill a medimnos measure, but there is one left over that you cannot fit into that measure.' In another version (Pherecydes) the question is the number of piglets in the belly of a pregnant sow; Mopsus says 'three, one of them female.' In both accounts it is Mopsus who gives the right answer; and the defeated Calchas dies there, of grief.
But the legend has more than one face. According to Sophocles, Calchas's death takes place not at Klaros but in Cilicia; some sources count him among the founders of Perge and Selge. The ancient world kept many versions of the same story alive side by side.
