Alexius I reforms Byzantine coinage

manuel comnenus scyphate (cup-shaped) hyperpyron.

former money changer michael iv paphlagonian (1034–41) assumed throne of byzantium in 1034 , began slow process of debasing both tetarteron nomisma , histamenon nomisma. debasement gradual @ first, accelerated rapidly. 21 carats (87.5% pure) during reign of constantine ix (1042–1055), 18 carats (75%) under constantine x (1059–1067), 16 carats (66.7%) under romanus iv (1068–1071), 14 carats (58%) under michael vii (1071–1078), 8 carats (33%) under nicephorus iii (1078–1081) , 0 8 carats during first eleven years of reign of alexius (1081–1118). under alexius comnenus (1081–1118) debased solidus (tetarteron , histamenon) discontinued , gold coinage of higher fineness (generally .900-.950) established, commonly called hyperpyron @ 4.45 grs. hyperpyron smaller solidus.

it introduced along electrum aspron trachy worth third of hyperpyron , 25% gold , 75% silver, billon aspron trachy or stamenon valued @ 48 hyperpyron , 7% silver wash , copper tetarteron , noummion worth 18 , 36 billon aspron trachy.