It was only towards the end of the seventeenth century that 'diplomacy' began to attain the meaning we attribute to it today. In 1693, Gottfried Leibniz published his Codex Juris Gentium Diplomaticus, a collection of treaties and official documents which attributed “to the adjective diplomatic the meaning of something related to international relations” . Other European powers followed suit in commissioning large archiving activities such as this; the diploma thus became organised and was a vital resource for statecraft.
However, it wasn't until 1796 that we find 'diplomacy' in its modern form in the writings of Edmund Burke who spoke of the ‘diplomatic body,’ and used “‘diplomacy’ to mean skill … in the conduct of international intercourse and negotiations” . In seventeenth-century Italy, diplomatic agents had become known as “orators” and in most of Europe “ambassadors were still legati” .
While the basic elements of the practice of diplomacy may therefore be as old as human being, the word and concept are of quite recent genesis. It's informative to mention at this point the origin of 'theory':
… the Greek practice theôria [is] the etymological precursor to the English word theory. In George Rawlinson's translation of Herodotus, theôria is rendered only as "to see the world," yet theôros has multiple meanings, including a spectator, a state delegate to a festival in another city, and someone who travels to consult an oracle. Theôria is itself a compound of different etymological possibilities: the first half of the word suggests both vision (thea, meaning sight/spectacle) and God (theos), while -oros connotes "one who sees." Unsurprisingly, then, theôrein is the verb meaning "to observe" and is connected to sightseeing and religious emissaries. This etymology posits a link among theôria, travel, direct experience, and vision, but it is in Herodotus's Histories that such practices are tied specifically to the achievement of knowledge: in one of the earliest known uses of the word theôria in the ancient world, Herodotus describes Solon the Lawgiver's journey from Athens for (among other reasons) the sake of theôria and explicitly links theory and wisdom (sophia) to travel across vast terrain (1.30.2). Herodotus reiterates the association among theory, travel, and knowledge when he describes Anacharsis the Scythian (4.76.2) as one who "had traversed much of the world on a theôria and throughout this had given evidence of his great wisdom." The practical precursor of diplomacy might have been theory (Constantinou makes this point extensively). We could call the 'diplomacy' articulated by Isabelle Stengers and Bruno Latour, therefore, a fittingly theoretical diplomacy. Wisdom, travel, religion and interpolitical relations are all tied up in this web of connections. However, diplomacy, as Stengers and Latour deploy the concept, is rather different to its historical precursors.
The diplomat was once the bearer of the diploma, the emissary that the folded document confirmed. The issues which motivated his journey were borne otherwise; the purpose of the diploma was to authenticate the authority of the received utterances [the science dedicated to the authentication of official documents: 'diplomatics']. It was crucial to the mission but was not its cause.
The folded object remains central to 'cosmopolitical' diplomacy but takes on a different role to one of mere passport. The diploma now does not simply authenticate the diplomat's right to speak but forms precisely the foundation of the entire endeavour.
If the heart of diplomacy remains the diplo-ma – the folded object/document, the duplex entity – then what does this make the diplomat? The diplomat is not the folder of objects (its sovereign – its public – is that which has folded the object and dispatched the envoy). The diplomat is the unfolder of objects that cannot be unfolded by one party. It is as though the causal issues were a giant bed-sheet impossible to fold or unfold by one person alone. The cosmopolitical diplomat is a burdened traveller in search of unfolding that can only come with the meeting of an other.
The diplomat is the one who arrives bearing the folded object but, unlike a mere herald, messenger or legati, is greeted, is subject to elaborate ceremonial attachment to the receiving community and who becomes resident so as to work through the matters at hand – the matters present-at-hand, we might say (the essence of the diploma qua passport was its very unproblematic, indubitable readiness-to-hand).
The duplex character of the diplomatic matter indicates its issue-hood, its status as a matter of concern, of contestation, of disagreement, dissensus, discord. Diplomacy always begins in duplicity; if successful it ends not in unity but in settlement.
The diplomat of this procedure is a transformed character, a theôros – a philosopher, indeed!
 Costas Constantinou, On the Way to Diplomacy, p.77.
 José Calvet de Magalhães, The Pure Concept of Diplomacy, p.58.
 Constantinou, On the Way to Diplomacy, p.77.
 Magalhães, The Pure Concept of Diplomacy, p.58.
 Ernest Mason Satow, A Guide to Diplomatic Practice, p.3.
 Garrett Mattingly, Renaissance Diplomacy, p.130.
 Roxanne L. Euben, Journeys to the Other Shore: Muslim and Western Travelers in Search of Knowledge, p.21.