ISLAMIC, Arabia. Rasulid. al-Mansur 'Umar I, AH 626-647 / AD 1229–1250. Dirham (Silver, 24 mm, 1.87 g), type D, Aden, AH 641 = 1243/4. Within double intersecting trefoils, ‘lā ilāha illā / Allāh Muḥammad rasū/l Allāh’ (‘There is no deity but Allah. Muhammad is the messenger of Allah’ in Arabic); in the margin, ‘al-aʾimma Abūbakr al-ṣiddīq ʿUmar al-fārūq ʿUthmān dhū al-nūrayn ʿAlī Abu’l-Ḥasan’ (‘The Imams, Abubakr the Upright, ʿUmar the Distinguisher between Truth and Falsehood, ʿUthman the Possessor of Two Lights, ʿAli the Father of al-Hasan’ in Arabic). Rev. Within double intersecting trefoils, citing the ʿAbbasid caliph al-Mustaʿsim billah (AH 640-656 / AD 1242-1258) ‘al-Mustaʿṣim / billāh amīr al-muʾminīn / al-Manṣūr ʿUmar’ (‘al-Mustaʿsim billah, Commander of the Believers. al-Mansur ʿUmar’ in Arabic); continued in the margin, ‘al-malik ibn ʿAlī al-yamānī al-imām ḍuriba bi ʿAdan sana aḥad arbaʿīn sitta miʾa’ (‘the king, son of Ali, the Yamani, the Imam. Struck in Aden in the year 641’ in Arabic). Album 1100.4. Rare. Areas of weakness and with some scratches and deposits, otherwise, very fine.