Muhammad Ahmad, "the Mahdi", Riyal of 20-Piastres, without mint name, struck at Umm Darman, dated 1302, regnal year 5 AH/1888 AD, similar to preceding lot (Dav.62; KM.2), mount marks on edge at 3 o'clock and at 8-9 o'clock on reverse, slight scratches in field to right of date, otherwise good very fine, rare