In IG XII(5), 608 Lachon also appears to have won two boys' competitions (one of them also a stadion-race?). Or was the repetition an error? Moretti 1957, no. 288 states that these were victories at the Nemea. Their dating should be very close to the Olympic victory of Lachon: 455 or 453 BC?
Lachon of Keos, son of Aristomenes, was victorious twice in some boys’ discipline at the Nemea, probably in succesive iterations of the games for the date of those two victories, if Lachon won as a παῖς at Olympia in 452 BC, before his two Nemean victories, then probably won the Nemean victories in 451 and 449. He would have been not older than 16 (and still a παῖς in Nemean terms) and not older than 14 in 451 BC and not older, therefore, than 13, when he won his Olympic victory, despite being up against opponents of 17 years or so(Schmidt, 1999). - EK