John of Seville (Johannes Hispalensis, active c. 1133-1153) is a central figure of the Toledo School of Translators and the main channel for Arabic astronomy and arithmetic entering 12th-century Latin Europe. His most influential work is the literal translation of Abu Ma'shar's Kitab al-mudkhal al-kabir (1133, Introductorium in Astronomiam), independent of Hermann of Carinthia's freer 1140 version. He also translated Arabic treatises on the astrolabe by Mashallah and Ibn al-Saffar, and positional-arithmetic texts attributed to Al-Khwarizmi.