Abū Ḥafṣ ‘Umar al-Murtaḍā (Arabic: أبو حفص عمر المرتضى بن أبي إبراهيم اسحاق بن يوسف بن عبد المؤمن; died 1266) was an Almohad caliph who reigned over part of present-day Morocco from 1248 until his death.
During his time as caliph, the area of Morocco under Almohad control was reduced to the region around and including Marrakesh. He was forced to pay tribute to the Marinids. He was ousted by his cousin Abu al-Ula al-Wathiq Idris with the help of Marinid ruler Abu Yusuf Yaqub ibn Abd Al-Haqq, with Idris II then proclaiming himself as caliph.
He was interested in Maghrebi script and established the first public manuscript transcription center at the madrasa of his mosque in Marrakesh.[1][2]