Histamenon

Ever since Emperor Constantine I (r. 306–337) introduced it in 309, the Byzantine Empire's main coinage had been the high-quality solidus or nomisma, which had remained standard in weight (4.55 grams) and gold content (24 carats) through the centuries.

[3][4][5] The reasons for this change are not clear; Byzantine chroniclers, however, suggest fiscal motives, reporting that Nikephoros collected the taxes as before in the histamenon while paying back with the tetarteron, which was officially rated as equal in value to the full-weight coin.

During the later reign of Basil II (r. 976–1025), the tetarteron began to be minted in a thicker and smaller form, while the histamenon became correspondingly thinner and wider.

In addition, under Michael IV the Paphlagonian (r. 1034–1041), it began to be minted in a slightly concave (scyphate) form, possibly to increase the thin coin's strength and to make it less easily bent.

[8][9][10][11] Starting with Michael IV, who was a former money lender, the gold content began to be increasingly lowered and the coins debased.