Abstract: In discussions of the role and value of axiomatic methods in physics, Newton's Principia is a common exemplar of axiomatics done well. Yet it is not clear in what precise sense Newton employs an axiomatic method, nor why this particular version proved to be so successful for his purposes in physics. In this talk, I will assess these two questions concerning Newton's distinctive methodology. I will argue that Newton deploys a version of the axiomatic method broadly inspired by the scholastic tradition of regressus, the twin method of analysis and composition. I will isolate Newton's axiomatics to the composition phase of the regressus so applied. Furthermore, I will suggest that his success in deploying this distinctive axiomatic method to physics is due in part to the analysis phase of the regressus. Newton's distinctive application of analysis through experimentation ensures that his empiricism regiments his rationalism.