Leonhard Euler (April 15, 1707–September 18, 1783) was a devout Christian (Calvinist) who became the greatest mathematician of the eighteenth century and perhaps the most productive of all time. Born in Switzerland to a Calvinist pastor, Euler published 886 papers and his complete works consume about 90 volumes. The St. Petersburg Academy, where Euler worked after been raised in Switzerland and spending some time in Berlin, spent 30 more years after Euler died in continuing to publish his work. Yet much of Euler's work was done when he was completely blind.
Interestingly, Euler had extraordinary powers of concentration. He could recite the entire Aeneid word-for-word. He could work amid noise and distractions. He could do phenomenal calculations in his head, which became very useful after he went blind in 1766.
Euler was perhaps the greatest scientist/mathematician that Switzerland ever produced.