The books were given to the trust of two Roman patricians (nobles). Beginning in 367 BC, ten keepers - five from the patricians and five from the common citizens - were appointed for them. After this (possibly the time of Sulla, 88-78 BC), the number of keepers was increased to fifteen. The job of these keepers was to consult the books on what was the right action or ceremony to escape from threats. Even so, they would not reveal the prophecies themselves, but only tell the action or ceremony needed.