• Webster's Revised Unabridged Dictionary
    • Datary (R. C. Ch) An officer in the pope's court, having charge of the Dataria.
    • Datary The office or employment of a datary.
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Century Dictionary and Cyclopedia
    • n datary An officer of the chancery at Rome, who directly represents the pope in all matters relating to grants, dispensations, etc. All petitions pass through his hands; he has the right of granting benefices not exceeding an annual value of 24 ducats; and with him solely rests the duty of registering and dating all bulls and other documents issued from the Vatican. He is generally a bishop, and is assisted by a subdatary, who is also in holy orders. When a cardinal is elected to the office of datary he bears the title of prodatary. See datary.
    • n datary The office or duty of dating and despatching papal documents; specifically, a branch of the Curia at Rome, established about the end of the thirteenth century by Pope Boniface VIII., for the purpose of dating, registering, and despatching all bulls and documents issued by the pope, examining and reporting upon petitions, etc., and granting favors and dispensations under certain conditions and limitations. See datary.
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Chambers's Twentieth Century Dictionary
    • n Datary dā′ta-ri an officer in the papal chancery, who dates and despatches documents, grants, &c
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Webster's Revised Unabridged Dictionary
LL. datarius,. See Dataria
Chambers's Twentieth Century Dictionary
Low L. datarius—L. datumdăre, to give.


In literature:

The Datary has asserted that he meant he should be master over Charlemagne.
"A Philosophical Dictionary, Volume 1 (of 10)" by François-Marie Arouet (AKA Voltaire)
The Pope and his Datary refused to interfere in this ignoble quarrel.
"Renaissance in Italy: Italian Literature" by John Addington Symonds
But I'll lay a Wager, that he will do nothing more than see the Datary and the Rota with a round Sum of Money.
"The Memoirs of Charles-Lewis, Baron de Pollnitz, Volume II" by Karl Ludwig von Pöllnitz