Digital library collections may appear static, but usually contain content from many di erent time periods. What changes when your collection is a diachronic corpus spanning decades or even centuries? The temporal structure is a lightweight annotation that provides powerful new handles for users to explore the collection, and engage with the material from many di erent angles. There are also fundamental consequences for the design of digital library systems and back o ce systems empowering curators and digital humanities researchers to explore the data at scale. We study this question for collections of parliamentary proceedings spanning multiple centuries in a uniform format. Jaap Kamps is an associate professor of information retrieval at the University of Amsterdam, PI of a stream of large research projects on information access funded by NWO and the EU, vice-chair of the ACM SIG-IR, organizer of evaluation e orts at TREC and CLEF, and a proli c organizer of conferences and workshops. His research interests span all facets of information storage and retrieval { from user-centric to system-centric, and from basic research to applied research. A common element is the combination of textual information with additional structure, such as document structure, Web-link structure, and/or contextual information, such as meta-data, anchors, tags, clicks, or pro les.