In fifteen years of research I have acquired debts too numerous to repay as they deserve. Without the staff of the Russian State Archive of Ancient Documents, and in particular M. P. Lukichev and S. R. Dolgova, the work could not have been done at all. I owe thanks as well to the staff of the Haus- Hof- und Staatsarchiv in Vienna, and in particular to Dr. Leopold Auer. My thanks are due to the Svenska Riksarkiv in Stockholm, the Danska Rigsarkiv in Copenhagen, the Algemeene Rijksarchiev in the Hague, the Public Record Office in London, and the archive of the Ministry of Foreign Affairs of France in Paris. Many libraries as well have helped enormously, the Historical Library and the Russian State Library in Moscow, the Russian National Library (Publichka) in St. Petersburg, the British Library, and the Slavic Library of the University of Helsinki (and especially Irina Lukka) all made my work easier. My greatest debt among librarians goes to the staff of the Sterling Memorial and Beinecke Libraries at Yale University. Tatjana Lorković and Susanne Roberts were an unfailing source of assistance and provided me with a continuous stream of new and old material. The Interlibrary Loan office, Maureen Jones and Liz Johnson, found arcane and unknown works in the most unlikely places. The Circulation Desk staff, Barbara Gajewski, Pearlene Ford, and their colleagues solved more problems than could ever be imagined.