Confusion exists over the identity of al-Jayyānī of the same name mentioned by ibn Bashkuwal (died 1183), Qur'anic scholar, Arabic Philologist, and expert in inheritance laws (farāʾiḍī).
However, E. S. Kennedy points out that while it was possible in pre-Islamic mathematics to compute the magnitudes of a spherical figure, in principle, by use of the table of chords and Menelaus' theorem, the application of the theorem to spherical problems was very difficult in practice.
[5] There is strong consensus in attributing the authorship of a manuscript about the duration of twilight to him.
[8] The short treatise On twilight was incorrectly attributed to Ibn al-Haytham for several centuries, due to a reference made by Gerard of Cremona, who translated it into Latin.
The first printed edition of Cremona's translation (Allacen arabis uetustissimi liber de crepusculis, Gerardo Cremonensi interprete) was made in 1542, by the Portuguese mathematician and cosmographer Pedro Nunes.