The vicecancellarius of the later medieval papacy was an extremely powerful position. There was no cancellarius - that was the pope himself - so the vicecancellarius, as his name suggests, oversaw the running and operations of the papal chancery, though it's unlikely that someone like Borgia would concern himself with most of the day to day.

The late medieval papal chancery was a bureaucratic organ tasked with the creation and archiving of correspondence between the papacy and Christendom, and employed at least one to two hundred scribes. If a petitioner, whether king or peasant, asked for something, the chancery recorded their letter; if the pope granted the petition, the chancery recorded the grant; it archived both so as to verify claims made. Medieval scripts varied greatly by region, and the chancery scribes often mimic'd the form. If the pope wished to issue a decree, called a bulla from the massive lead seal affixed to such documents, a special set of scribes were tasked with drawing it up with all the necessary anti-forgery devices. The level of correspondence was such that the dataria was established in the 15th century to deal with benefices and other grants within the papacy's purview.

All this meant that if someone wanted something from the papacy, having the ear of the vicecancellarius was a pretty good way to go about getting it. As structures of patronage were (and are) the foundations upon which political power is built, the holder of the office was necessarily a major political player.

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