Abū Isḥāq Ibrāhīm b. Yaḥyā l-Naqqāsh al-Tujībī (d. 493/1100), called Ibn al-Zarqālluh , was the most important western Islamic astronomer of the Middle Ages. He was known also as Walad al-Zarqiyāl (whence the Hispanicised form Azarquiel), al-Zarqālluh, al-Zarqāl, and Ibn Zarqāl. Al-Zarqālī (sometimes al-Zarqānī) and al-Zarqāla appear to be classicised Eastern forms. The name is occasionally written also as al-Zarqāllu and Zarqallu. He was an instrument maker in Toledo and worked, after 440/1048-9, for the scholar and historian