WELL before the contested edition of Flamsteed's Historia coelestis in 1712 brought that episode to a temporary conclusion, two new concerns, which would dominate Newton's life for more than five years, had imposed themselves upon him. In 1709, work began in earnest on a second edition of the Principia. In the spring of 1711, a letter from Leibniz to Hans Sloane, secretary of the Royal Society, inaugurated a heated controversy over claims of priority in the invention of the calculus. Moreover, a fourth problem of great import for Newton was also taking form. Already an ugly scene with Craven Peyton, the warden of the Mint, had signaled a deterioration of their relations which culminated in a major crisis in the Mint in 1714, when the battle with Leibniz was reaching its highest pitch. The Mint was the bedrock on which Newton's existence in London stood. Trouble there had to affect his whole life. In its intensity, the period from 1711 to 1716, succeeding more than a decade of relative calm, matched the great periods of stress at Cambridge, when his relentless pursuit of truth stretched him to the limit. The coincidence of these events, the demands they placed on Newton, may help to explain the furious scene with Flamsteed at Crane Court on 26 October 1711 and much else from these years not yet mentioned.