⅙ 'Sudaysi' Dirham - al-Nasir Ahmad Zaidi imam

The Rassid (or Zaydi) imamate of Yemen operated one of the most fractional silver coinage systems in the medieval Islamic world, producing subdivisions small enough that most have not survived intact. Ahmad ibn Yahya al-Nasir, who consolidated Zaydi authority in the Yemeni highlands during the early tenth century, issued these tiny sudaysi fractions — one-sixth of a dirham — primarily to meet the demands of local market exchange where full dirhams were too valuable for daily transactions. At 0.19 g, losses to wear, clipping, and simple misplacement were inevitable.