In 2016, the University of Pennsylvania Libraries, along with fourteen partnering institutions in the Philadelphia area, was awarded a grant from the Digitizing Hidden Special Collections and Archives initiative of the Council on Library and Information Resources (CLIR) to produce the United States' largest regional online collection of medieval manuscripts. For the Bibliotheca Philadelphiensis project, otherwise known as BiblioPhilly, partnering institutions had thirty months to digitize more than 160,000 pages from 450 European medieval and early modern manuscripts. According to the terms of the grant, the digitized manuscripts had to be made available in the public domain via a searchable digital interface, be easily downloadable at high resolution, and accompanied by both expertly compiled descriptive metadata and unique physical collation models that help researchers to date manuscripts, understand how codices were disassembled and reconstructed in different periods, recombine fragments, and much more. While the BiblioPhilly project required intensive data capture from photographers and catalogers along with specific, timesensitive, and particularly careful handling conditions, the process functioned smoothly through project management and a cooperative spirit among colleagues. As a result of these efforts, researchers may now creatively interact with the materiality of a manuscript in a digital environment in a manner that would be impossible with the physical manuscript itself. In a manner new to the field, BiblioPhilly enables researchers to become not just assessors of, but participants in, a long history of manuscript repurposing, reconstruction, and transformation.