This paper is an investigation into the introduction of the term ‘system’ and its conceptual background in the writings of Bartholomew Keckermann. This includes a brief summary of the literature and evidence identifying Keckermann as the first to make significant usage of the term in logic, philosophy, and theology. Then, after a survey of his life, work and milieu, this paper will look closer at three of Keckermann’s own ‘systems’; Systema logicae (1600), Praecognitorum Logicorum (1606), and Systema SS. Theologiae (1602). Finally, I will touch on the influence Keckermann’s innovation had on subsequent ideas of method in modern philosophy, especially how his innovative use of this term gives the logician the directing role as a technical expert in mining the truth of theology, philosophy, and other sciences. This, of course, flies in the face of the medieval view of the Church and its elders controlling that role, characterizing the discovery and refinement of knowledge as being a process of electing and using worthy passive subjects as conduits of divine knowledge. Thus Keckermann’s systems can be considered an important step away from this, towards the early modern epistemology requiring an active thinking subject, best characterized in Descartes’ Meditations.