We utilised PDF files from the 2013 digitisation by <hi xmlns="http://www.tei-c.org/ns/1.0" rend="italic">arpa Data GmbH</hi>,<ref xmlns="http://www.tei-c.org/ns/1.0" n="4" target="ftn4" /> along with TUSTEP files where available, to extract texts and footnotes. Challenges in footnote extraction included varying layouts, multi-page footnotes, nested footnotes, OCR errors, and overflow of the footnote apparatus of one letter into the one of the subsequent letters. We converted the extracted data to TEI/XML format, employing control scripts and manual intervention when necessary.<ref xmlns="http://www.tei-c.org/ns/1.0" n="5" target="ftn5" />