Albertus Magnus taught at Paris and later at Cologne, and among his students at Paris was a young Dominican named Thomas Aquinas, whose Summa Theologiae and broader synthesis of Aristotelian philosophy with Christian theology built on groundwork Albertus had laid in his own vast commentaries on Aristotle. Albertus was, by the range of his own writing, exactly the kind of scholar who could lay that groundwork: alongside theology and logic he wrote systematically on botany, zoology, mineralogy and natural philosophy, treating the created world as an object of patient, empirical study rather than only theological allegory. He served briefly as bishop of Regensburg before returning to teaching, and was canonized by Pope Pius XI in 1931; a decade later, in 1941, Pope Pius XII declared him patron saint of natural scientists.
That genuine scholarly range also made him an irresistible name for others to borrow. From at least the fourteenth century onward, a body of pseudonymous alchemical and magical texts circulated under his name, most persistently a popular compendium of herbal, animal and mineral "secrets" known in English as the Book of Secrets, offering recipes and occult properties with no real connection to Albertus's own careful, source-citing scholastic method. Modern scholarship does not accept the Book of Secrets or its companion works as genuinely his; they belong to the long practice of attaching a revered scholar's name to material meant to borrow his authority, the same practice that produced pseudonymous works under Aristotle's and Hermes Trismegistus's names. Albertus's own authenticated writings, not the grimoire tradition that grew up around his reputation afterward, are what earned him the title Doctor Universalis in his own lifetime.