Abstract The recent recovery of a well-tuned carillon of sixty-five bronze bells, from a tomb dating to 433 BC, is one of the most startling musical archeological events of all time. The five-octave, chromatic chime-set, with most of its bells tuned to the ‘philosophical pitch standard’ (middle C = 256 cps), is a sophisticated achievement beyond the reach of Western science and technology for another two thousand years. Some 2800 characters inscribed on the bells and the bell-stand name the tones within both a ‘relative pitch’ system and an ‘absolute pitch’ system, the latter in the key of A-flat, related directly to the calendar. Alternate tunings together with the inscriptions suggest that this funerary set may have been conceived as both an acoustical laboratory and a musicological library. Coincidences between abstract Chinese tone ratios and measured frequencies of the largest bells suggest that Zeng acousticians may have been able to make accurate frequency determinations. Patterns in both the tuning and the naming system, never known to historians, now show that in the fifth century BC the tone systems of China and Greece shared extensive structural similarities. This new archeological evidence thus strengthens the hypothesis that an ancient Mesopotamian biophysics linking number, tone, and calendar enjoyed a pan-Eurasian development.