Agamedes

He and his brother, Trophonius, were the sons of Erginos; they were renowned architects and credited with building the temple of Apollon in the city of Delphi.

Agamedes and his brother were also said to have built the treasury of Hyrieus (or Augeas) and to have designed it in such a way that they could come back later and rob it.

During the attempted robbery, Agamedes became ensnared in a trap inside the treasury and Trophonius was unable to free him; in a desperate attempt to conceal his brother’s identity, Trophonius cut off Agamedes’ head; afterwards, near the city of Lebadeia in Boeotia, Trophonius was swallowed by the earth and an oracular site was established in his name; supplicants would enter the cave and, after receiving the prophecies and omens imparted by Trophonius, would emerge pale and shaken.