As stated in the first preface, this work was supposed to come out in three volumes. It has grown to four. Like other living things books tend to become reproductive. We think we write them, but sometimes they seem to write themselves. Also, while we like to think we do things by ourselves, mostly we do not. Without the assistance I have received I should never have been able to finish this work. Over the years Mrs. Jean T. Carver has prepared the typescripts, and read both the galleys and the page proofs. Dr. Susan M. Babbitt has checked both typescript and proofs, and she has made the index to these last two volumes (tantae molis erat!). I am most grateful to them both. The dedication of these volumes to my wife is much more than a thankful gesture. She has entered the archives with me, copied documents, criticized the typescript, and read the proofs. Besides all this she has transcribed the text of Pietro Valderio's Guerra di Cipro, which work has (I think) not hitherto been used for the critical years 1570-1571. Again I must acknowledge my years-long debt to the archivists and librarians at the Vatican and in Venice, at Mantua and Malta, Modena and Milan, Siena and Florence. I recall with pleasure my long sojourn at the Gennadeion in Athens, and with equal pleasure I acknowledge my indebtedness to Dr. Harry Woolf, director of the Institute for Advanced Study; Dr. Herman H. Goldstine, executive officer and editor of the American Philosophical Society; Miss Carole N. LeFaivre, assistant editor of the Society; and Dr. Harry W. Hazard, my fellow editor of the History of the Crusades.

As in the earlier volumes the chapter headings are descriptive, designed to indicate the content and chronological coverage of each chapter. There are too many important issues discussed, too many events described, in the following pages to make it advisable to single any of them out for comment. We must, however, lay some stress on the fact that in the sixteenth century the Holy See had to face not only the Protestant revolt but also the Turkish peril, and that the two problems were (as we shall see) always closely related. The popes had also to deal with the hostile rivalry of France and Spain,