Zaydî Imams
al-Mahdî Ahmad ibn al-Husayn, 646-655 H./1248-1257 AD Quarter mahdawî dirham or 1/6 dirham qifla undated, Ta'izz. Quatrefoils within and around a square like the mahdawi standard type on both sides. Album, Checklist 1085A Var. 0.41 g.; Extremely rare and unpublished Extremely fine
The mint is of course not Ta'izz in the lower Yaman, but a place of the same name near Sa'da, mentioned several times in the Kitâb as-simt, see Smith, Ayyubids II p. 208.