The three surviving books of the Sibyl Amalthaea were preserved in a stone chest underground in the temple of Jupiter Capitolinus, and committed to the charge of custodians chosen in the same manner as the high priests. The number of custodians was at first two, then ten, and ultimately fifteen. The books were destroyed by fire when the Capitol was burnt (A.D. 670).
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
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