Among the many artefacts in the Ashmolean Museum in Oxford, England, lies a unique but largely forgotten clay tablet inscribed some four thousand years ago in the cuneiform language of ancient Mesopotamia. It takes the form of a prism covered in tiny neat signs laid out in careful order across its four surfaces. And since it arrived in that place, it has been vainly signalling that something of great importance is written on it, that the information it contains was once considered of great value. Look more closely. There is so much about it that has been left unsaid. So much has been missed. In truth, the tablet tells a unique story: that of a great astronomer, a maestro of the skies on a quest to relay age-old information to future generations. Amongst its numerous encoded messages, it confirms that the mysteries embodied in the Giza plateau in Egypt, its pyramids and its Great Sphinx, were indeed described in the writings of the so-called 'Sumerians'. At the source of it all is the wisdom teacher known to us as Thoth who is also Hermes Trismegistus, author of the equally unique and enigmatic Emerald Tablet. Every aspect of the artefact is involved in the process of the telling; its lines laid out to encode numbers of importance in astronomy, geometry, music... They integrate the 25,920-year cycle of time called the precession of the equinoxes, and the number known as Pi, used to calculate the circumference of a circle. There was once a shaft through the hole at its centre, serving to turn the prism in an anticlockwise direction, thus imitating the flow of the sun and gloriously decoding the most perfect musical pitch. Not only that. It tells us that other extremely ancient sites, those recently uncovered in southeastern Turkey - Goebekli Tepe, Karahan Tepe, Sayburc - and another in the distant land of Peru, all carry signs of the Great Egyptian Maestro. They too dance to his music and, however softly spoken He may be, His great work can no longer be ignored.