Only when a formal announcement of the history was made in the _North American Review_ in 1837, did even his familiar associates begin to think of him as an author. The death of Prescott's little daughter, Catherine, in February, 1829, did much to drive him to hard work as a relief from sorrow. She was his first-born child, and when she died, she was a few months over four years of age,--a winsome little creature, upon whom her father had lavished an unstinted affection. She alone had the privilege of interrupting him during his hours of work. Often she used to climb up to his study and put an end to the most profound researches, greatly, it is recorded, to the delight of his secretary, who thus got a little moment of relief from the deciphering of almost undecipherable scrawls. Her death was sudden, and the shock of it was therefore all the greater. Years afterward, Prescott, in writing to a friend who had suffered a like bereavement, disclosed the depths of his own anguish: "I can never suffer again as I then did. It was my first heavy sorrow, and I suppose we cannot twice feel so bitterly." His labour now took on the character of a solace, and perhaps it was at this time that he formed the opinion which he set down long after: "I am convinced that intellectual occupation--steady, regular, literary occupation--is the true vocation for me, indispensable to my happiness." And so his preparation for _Ferdinand and Isabella_ went on apace. Prescott no longer thought it enough to master the historians who had already written of this reign. He went back of them to the very _Quellen_, having learned that the true historical investigator can afford to slight no possible source of information,--that nothing, good, bad, or indifferent, can safely be neglected. The packets which now reached him from Spain and France grew bulkier and their contents more diversified. Not merely modern tomes, not merely printed books were there, but parchments in quaint and crabbed script, to be laboriously deciphered by his secretary, with masses of black-letter and copies of ancient archives, from which some precious fact or chance corroboration might be drawn by inquisitive industry. The sifting out of all this rubbish-heap went on with infinite patience, until at last his notes and memoranda contained the substance of all that was essential.