Ever since the creation of the Byzantine monetary system by Constantine in 312, its pivot had been golden "solidus", a coinage whose nominal value was equal to its intrinsic value, as is proven by the Theodosian Code. "Solidus" became a highly priced and stable means of storing and transferring values Novel 16 of Valentinian III punished with death anyone who dared "refuse or reduce a gold "solidus" of good weight." Weight and fineness of the coinage were joined by another element: the authenticity of the stamp, which served to guarantee the other two. Alongside this "real"-value gold coinage, and a slightly overvalued silver coinage, there was also a bronze coinage of a fiduciary nature that made up the second specific feature of the monetary system. At the end of the 10th and in the 11th centuries, money underwent a profound transformation, followed by a crisis; the denomination affected all metals at different dates, and according to different modalities. The reform of Alexios I Komnenos put an end to this crisis by restoring a gold coinage of high fineness, the "hyperpyron", and by creating a new system destined to endure for about two centuries.