 Barrow conceived of continuous magnitudes as being generated by motions, and so necessarily dependent on time, a view that seems to have had a strong influence on the thinking of his illustrious pupil Isaac  Newton[18]  (1642–1727). Newton’s meditations during the plague year 1665–66 issued in the invention of what he called the “Calculus of Fluxions”, the principles and methods of which were presented in three tracts published many years after they were written: De analysi per aequationes numero terminorum infinitas; Methodus fluxionum et serierum infinitarum; and De quadratura curvarum. Newton’s approach to the calculus rests, even more firmly than did Barrow’s, on the conception of continua as being generated by motion.