As Marchand elucidates, it was most likely before his research trip to Rome in autumn 1928 that Warburg had all the material in the then-existent 72 boxes stamped with a number sequence identifying each individual item by its box and its place within the order of items across all boxes (so, for instance, the index card shown in Fig. 2. would be item number 10042 in the overall sequence). This detailed indexing allowed Warburg and Gertrud Bing to assemble a new set of Zettelkästen specifically for the Rome trip without worrying about irredeemably displacing any items from their original locations. These “travelling boxes” were never dismantled as planned, however, and are still part of the Archive today, recognisable by a separate numbering sequence marked in square brackets (e.g. ZK [1]). Although the square-bracketed Zettelkasten sequence now also includes other boxes that were unnumbered at Warburg’s death, the visible difference between the two sequences remains a testimony to the mobility of the Zettelkasten corpus and its role in Warburg’s work on the famous Bilderatlas, a central part of which occurred during the abovementioned Rome trip with Bing.