In the only architectural treatise surviving from Classical Antiquity, Vitruvius: Ten Books on Architecture refers in some detail to adobe, describing suitable earth and suggesting that adobes should be made in the spring and left for at least two years to dry. He mentions that building by-laws in Utica (near Carhage) specify that only adobes of five years old be used for building, to be so certified by the aedile (magistrate).