 Calvin's ideas became popular in Bourges and the doctrine of the Reformation spread throughout the region and France.Calvinism became influential in Sancerre in 1540.After the Conspiracy of Amboise and Massacre (1560), many Huguenots took refuge in Sancerre, which became, along with Nîmes, Montauban and La Rochelle, one of the principal cities of the Reformation in France.