<hi xmlns="http://www.tei-c.org/ns/1.0" style="font-size:12pt">In contrast to other historical archives whose inventories are based on International Standard Archival Description (International Council on Archives, 2000) that allow for interoperability of data, the Vatican Archive is so immense and complex</hi><ref xmlns="http://www.tei-c.org/ns/1.0" n="2" target="ftn2" /> <hi xmlns="http://www.tei-c.org/ns/1.0" style="font-size:12pt" xml:space="preserve"> that it has not yet been equipped with a modern archival description system. Bear in mind that there is still no uniform archive guide, no comprehensive inventory, and that researchers often have to consult indexes and handwritten inventories, even dating back to the 14</hi> <hi xmlns="http://www.tei-c.org/ns/1.0" rend="superscript" style="font-size:12pt">th</hi> <hi xmlns="http://www.tei-c.org/ns/1.0" style="font-size:12pt" xml:space="preserve"> century, in order to know the contents of the archive series and select the documents they are interested in. Moreover, for reasons of document ownership and authenticity, the archive's policy is clearly resistant to an open access approach to data: documents cannot be photographed by researchers. Digital reproductions are expensive and can only be used for personal research purposes. Handwriting recognition software,</hi><ref xmlns="http://www.tei-c.org/ns/1.0" n="3" target="ftn3" /> <hi xmlns="http://www.tei-c.org/ns/1.0" style="font-size:12pt" xml:space="preserve"> which usually foresee the sharing of digitized images with other users, cannot be used to 'read' these documents.</hi><ref xmlns="http://www.tei-c.org/ns/1.0" n="4" target="ftn4" /> <hi xmlns="http://www.tei-c.org/ns/1.0" style="font-size:12pt" xml:space="preserve"> A final aspect that makes the documents preserved in the Vatican Archives hardly accessible concerns the specific knowledge and skills needed to read, understand and interpret them. Although common to historical research in general, this aspect takes on an important significance in the case of papal documents for the exegesis of which it is necessary to master certain specific disciplines and techniques.</hi><ref xmlns="http://www.tei-c.org/ns/1.0" n="5" target="ftn5" />