What is "bybon"

Bybon or Bybon son of Phola (early 6th century BC) was a famous ancient Greek weight lifter. A block of red sandstone weighing 143.5 kg was found at Olympia, with the carved inscription "Bybon son of Phola, has lifted me over [his] head with one hand." The stone has a section carved out as a hand grip.

The stone is on display at the Archaeological Museum of Olympia.