[1] Originally from Khorasan,[2] he lived in Basra (in present day Iraq) during the reigns of the Abbasid caliphs al-Manṣūr and al-Ma’mūn, and was among those who introduced astrology and astronomy to Baghdad.

The Arabic phrase mā shā’ Allāh indicates a believer's acceptance of God's ordainment of good or ill fortune.

The eight and ninth orbs moving around the same poles also guarantees that the 12 stationary signs and the 12 mobile zodiacal constellations overlap.

[3] Mashallah was an advocate of the idea that the conjunctions of Saturn and Jupiter dictate the timing of important events on Earth.

[7] The Big Book of Births (كتاب المواليد الكبير) (14vols); The Twenty-One On Conjunctions, Religions and Sects (الواحد والعشرين في قرانات والأديان والملل); The Projection of [Astrological] Rays (مطرح الشعاع); The Meaning (المعاني); Construction and Operation of Astrolabes (صنعة الإسطرلابات والعمل بها); The Armillary Sphere (ذات الحلق); Rains and Winds (الأمطار والرياح); The Two Arrows (السهمين); Book known as The Seventh & Decimal (Ch.1 – The Beginning of Actions (ابتداء الأعمال); Ch.2 – Averting What Is Predestined (على دفع التدبير); Ch.3 – On Questions (في المسائل); Ch.4 – Testimonies of the Stars (شهادات الكواكب); Ch.5 – Happenings (الحدوث); Ch.6 Movement and Indications of the Two Luminaries [sun & moon]) (تسيير النيرين وما يدلان عليه); The Letters (الحروف); The Sultan (السلطان); The Journey (السفر); Preceptions (الأسعار) [note 2]; Nativities (المواليد); Revolution (Transfer) of the Years of Nativities (تحويل سني المواليد); Governments (Dynasties) and Sects (الدول والملل); Prediction (Judgement) Based on Conjunctions and Oppositions (الحكم على الاجتماعات والاستقبالات); The Sick (المرضى); Predictions (Judgements) Based On Constellations (Ṣūr)(الصور والحكم عليها);[1] Mashallah's treatise De mercibus (On Prices) is the oldest known scientific work extant in Arabic,[9] and the only work of his extant in its original Arabic.

[6] Mashallah's treatise on the astrolabe, which was translated from Arabic into Latin as De Astrolabii Compositione et Ultilitate, is the first known of its kind.

[clarification needed] The source of Geoffrey Chaucer's Treatise on the Astrolabe (1391) in Middle English is not known, but most of his ‘conclusions’ can be traced to a Latin translation of Mashallah's work, Compositio et Operatio Astrolabii.

Skeat's Treatise of the Astrolabe includes a collotype MS facsimile of the Latin version of the second part of Mashallah’s work, which parallels Chaucer's.

[13][page needed] De elementis et orbibus was included in Gregor Reisch's Margarita phylosophica (ed.

In 1981, Paul Kunitzsch argued that the treatise on the astrolabe long attributed to Mashallah is in fact written by Ibn al-Saffar.