Statue of Nikephoros III Botaneiates. NM 1907/8 KB΄ 418 (403)

From the 1040s onwards, the gradual and ultimately disastrous decline of the gold coinage began, which was intertwined with the general decline of the empire. The coinage was constantly weakening in weight and in pure gold content; the gold used from the mid-11th century for minting nominal gold coins was mixed with silver or silver and copper. At the same time, the depreciated istamenon acquired a concave shape in order to differentiate it from the older coins with a normal gold content. The istamenon coin of Nikephoros III Botaneiates had a content of only 8 carats of pure gold. The Byzantine gold coinage was restored only after 1092 and the fundamental monetary reform of Alexios I Komnenos.