The Mill Lane lecture rooms in Cambridge are full of voices, and it was very agreeable for an undergraduate of the early 1950s to have the chance of adding one more to them in the autumn term of 1995. Those who were kind enough to come and listen will find that the four lectures have been heavily rewritten since. But I have continued to think of them as lectures, and if some of them are now a little long for an hour's talk, they may make amends for the one which turned out to be ten minutes too short. I am very grateful to those who entertained me so nicely at the time, and especially to the Master of Trinity, Sir Michael Atiyah, to Patrick Collinson, Boyd Hilton, Peter Burke and Ulinka Rublack. This is also the moment to remember those whose gifts and tips have enabled me to deal with my subject less scantily than I should otherwise have done: Simon Ditchfield, Eamon Duffy, Steve Hindle, Amanda Lillie, Daniele Montanari, Adriano Prosperi, Mary Stevenson, Marc Venard, Danilo Zardin. Despatches from Italy have been particularly numerous and particularly welcome, and I hope I have done justice to them in the first lecture. More thanks to Libby Walker, who has turned my spotty typescript into an elegant printout; to Linda Randall, the copyeditor; and again and especially to Amanda Lillie, who put me in the way of finding the Sansovino statue which appears on the cover.