This contribution investigates the first treatise on natural theology intended as such by its author. Nicholas Bonetus is the author of this treatise. The article examines Bonetus' life, works, and commitment to Scotism before surveying Duns Scotus' views on natural theology. Scotus is shown to have been optimistic regarding whether some doctrines now regarded to be strictly theological, such as the Trinity, can be proven by pure reason. Bonetus followed in Scotus' footsteps. The article surveys Bonetus' fundamental ideas on the (...) nature of natural theology. It is shown that he organized the science along the lines of an Aristotelian science, with the result that natural theology has a subject, and attributes that are demonstrated of the subject. The subject according to Bonetus is the first immoveable mover, and the science demonstrates various attributes of God, such as divine intellect and will, from which Bonetus derives the Trinitarian processions. Following the article is an appendix containing descriptions of the manuscripts, where it is shown that the majority do name the text «theologia naturalis». (shrink)