recently suggested that knowledge of these results might have been transmitted to Europe through the trade route from Kerala by traders and Jesuit missionaries. Kerala was in continuous contact with China and Arabia, and, from around 1500, with Europe. The existence of communication routes and a suitable chronology certainly make such a transmission a possibility. However, there is no direct evidence by way of relevant manuscripts that such a transmission actually took place. According to David Bressoud, "there is no evidence that the Indian work of series was known beyond India, or even outside of Kerala, until the nineteenth century." Both Arab and Indian scholars made discoveries before the 17th century that are now considered a part of calculus. However, they did not, as Newton and Leibniz did, "combine many differing ideas under the two unifying themes of the derivative and the integral, show the connection between the two, and turn calculus into the great problem-solving tool we have today." The intellectual careers of both Newton and Leibniz are well-documented and there is no indication of their work not being their own; however, it is not known with certainty whether the immediate predecessors of Newton and Leibniz, "including, in particular, Fermat and Roberval, learned of some of the ideas of the Islamic and Indian mathematicians through sources we are not now aware." This is an active area of current research, especially in the manuscript collections of Spain and Maghreb. This research is being pursued, among other places, at the CNRS. See also Shulba Sutras Kerala school of astronomy and mathematics Surya Siddhanta Brahmagupta Srinivasa Ramanujan Bakhshali manuscript List of Indian mathematicians Indian science and technology Indian logic Indian astronomy History of mathematics List of numbers in Hindu scriptures Notes References . . . . . . . . . . . . . . . . . . . . . . . . . New edition with translation and commentary, (2 Vols.). . . . . . . . . . . . . . . . . . . Further reading Source books in Sanskrit . . . . . . External links Science and Mathematics in India An overview of Indian mathematics, MacTutor History of Mathematics Archive, St Andrews University, 2000. Indian Mathematicians Index of Ancient Indian mathematics, MacTutor History of Mathematics Archive, St Andrews University, 2004. Indian Mathematics: Redressing the balance, Student Projects in the History