Ibn al-Shatir
Al-Urdi is a member of the group of Islamic astronomers of the 13th and 14th centuries who were active in the criticism of the astronomical model presented in Ptolemy's "Almagest". Saliba (1979) identified Bodleian ms. Marsh 621 as a copy of Al-Urdi's "Kitāb al-Hayʾa", based on which he argued that Al-Urdi's contributions predated Al-Tusi. Otto E. Neugebauer in 1957 argued that the works of this group of astronomers, perhaps via Ibn al-Shatir, must have been received in 15th-century Europe and ultimately influenced the works of Copernicus.