The Tablet of the Elders is an artifact that features in He-Man and the Masters of the Universe.
This stone tablet was made by the Council of Elders following their war against the Snakemen when King Hiss was sealed into the Void located in Snake Mountain. Its contents included writings that detailed where they had hidden the Snakemen artifact known as the Serpent Ring which was a powerful weapon once used by King Hiss in ancient times. After Hiss's defeat, the Elders detailed the fact that they hid the Ring in the Caverns of Rakash in order to contain its terrible power. Upon its creation, the Tablet of the Elders was protected at the Hall of Wisdom until the Council of Elders transformed their power into the crystal orb that was relocated to Castle Grayskull.
Many years later, the Snakemen Tung Lashor and Sssqueeze both secretly travelled to the Hall of Wisdom which had been converted into a market place for traders. There, they pillaged the chambers used by the Elders until they found the Tablet of the Elders which they returned to their master who now resided in Subternia. Upon deciphering its contents, King Hiss used his new found knowledge to plot his new attempt at conquering Eternia by re-acquiring the Serpents Ring.