 All his decipherments were done by comparing the texts with known history.Grotefend published his deductions in 1802, but they were dismissed by the Academic community.It was only in 1823 that Grotefend's discovery was confirmed, when the French philologist Champollion, who had just deciphered Egyptian hieroglyphs, was able to read the Egytian dedication of a quadrilingual hieroglyph-cuneiform inscription on an alabaster vase in the Cabinet des Médailles, the "Caylus vase".