190 Reason and Its Rivals (ca. 1550– 1815)critics of politicians rather than as loyal assistants. Th e more unswervingly
one adopted reason as a guide, the more one could fi nd to criticize.
Another factor in the rise of the pragmatists— and a crucial one— was a
greater availability of material on which to work, that is, greater access to
evidence and information about what state practice actually was. Access to
two kinds of information was especially necessary. One was treaty texts. Th e
other was administrative and judicial rulings of states that were relevant to
international relations (such as regulations about maritime traffi c in coastal
waters or instructions to armed forces on the conduct of war).
Systematic study of the treaty practices of states began to become possible
only at the end of the seventeenth century. A pioneering fi gure in this pro-
cess was a French Benedictine monk named Jean Mabillon. His De re diplo-
matica (1681) founded the science of diplomatics, which is the study of the
authenticity of documents. Another important early fi gure in this area was
the German polymath Gottfried Wilhelm Leibniz. Among his many roles—
philosopher, mathematician, psychologist— was historian. His Codes Iuris
Gentium Diplomatici (1693) was one of the earliest compilations of treaty
texts. “Collections of treaties of alliance, of peace, of concessions,” asserted
Leibniz, “are... the elements which underpin and support the whole edifi ce
of history.” Th e immediate purpose behind his project was to provide sup-
port for legal claims by the Holy Roman Empire against France. But he ex-
pressed the hope that the chief value of these labors, in the longer term,
would be to further the understanding of the law of nations.
Other similar eff orts appeared at this time. In fact, in 1693, the very same
year that Leibniz’s collection was published, a collection of French treaties
was assembled by Frédéric Léonard, covering treaties from 1435 onward.
In 1700, in Amsterdam, a four- volume collection of treaties and other public
acts by Eu ro pe an states, from the dawn of the Christian era, was pub-
lished. In En gland, a massive collection of primary source documents,
known as Rymer’s Foedera, began to appear in 1704, inspired by the work of
Leibniz— and even credited generously by Leibniz as being superior to his
own eff ort. It remains an invaluable tool for historians. So does the work of
Jean Dumont, a French soldier and publisher who settled in the Netherlands
and eventually became offi cial historiographer to the Holy Roman Empire.
His massive Corps universel diplomatique du droit des gens began to be pub-
lished in Amsterdam in 1726, and remains a valuable scholarly resource to