Zīj as-Sindhind is a work of zij brought in the early 770s AD to the court of Caliph al-Mansur in Baghdad from Sindh in present day Pakistan. Al-Mansur requested an Arabic translation of this work from the Sanskrit. The 8th-century astronomer and translator Muḥammad ibn Ibrāhīm al-Fazārī is known to have contributed to this translation. In his book Ṭabaqāt al-ʼUmam "Categories of Nations", Said al-Andalusi informs that others who worked on it include ibn Sa'd and Muhammad ibn Musa al-Khwarizmi. He adds that its meaning is al-dahr al-dahir.