From the royal archives of Holland I have obtained many most important, entirely unpublished documents, by the aid of which I have endeavoured to verify, to illustrate, or sometimes to correct, the recitals of the elder national chroniclers; and I have derived the greatest profit from the invaluable series of Archives and Correspondence of the Orange-Nassau Family, given to the world by M. Groen van Prinsterer.  I desire to renew to that distinguished gentleman, and to that eminent scholar M. Bakhuyzen van den Brink, the expression of my gratitude for their constant kindness and advice during my residence at the Hague.  Nothing can exceed the courtesy which has been extended to me in Holland, and I am deeply grateful for the indulgence with which my efforts to illustrate the history of the country have been received where that history is best known.

I have also been much aided by the study of a portion of the Archives of Simancas, the originals of which are in the Archives de l’Empire in Paris, and which were most liberally laid before me through the kindness of M. le Comte de La Borde.

I have, further; enjoyed an inestimable advantage in the perusal of the whole correspondence between Philip II., his ministers, and governors, relating to the affairs of the Netherlands, from the epoch at which this work commences down to that monarch’s death.  Copies of this correspondence have been carefully made from the originals at Simancas by order of the Belgian Government, under the superintendence of the eminent archivist M. Gachard, who has already published a synopsis or abridgment of a portion of it in a French translation.  The translation and abridgment of so large a mass of papers, however, must necessarily occupy many years, and it may be long, therefore, before the whole of the correspondence—­and particularly that portion of it relating to the epoch occupied by these volumes sees the light.  It was, therefore, of the greatest importance for me to see the documents themselves unabridged and untranslated.  This privilege has been accorded me, and I desire to express my thanks to his Excellency M. van de Weyer, the distinguished representative of Belgium at the English Court, to whose friendly offices I am mainly indebted for the satisfaction of my wishes in this respect.  A letter from him to his Excellency M. Rogier, Minister of the Interior in Belgium—­who likewise took the most courteous interest in promoting my views—­obtained for me the permission thoroughly to study this correspondence; and I passed several months in Brussels, occupied with reading the whole of it from the year 1584 to the end of the reign of Philip II.

I was thus saved a long visit to the Archives of Simancas, for it would be impossible conscientiously to write the history of the epoch without a thorough examination of the correspondence of the King and his ministers.  I venture to hope, therefore—­whatever judgment may be passed upon my own labours—­that this work may be thought to possess an intrinsic value; for the various materials of which it is composed are original, and—­so far as I am aware—­have not been made use of by any historical writer.