In an aside in an article about the greatest human innovations where he proposes the relational database as a candidate, Tim Worstall quotes the following comment about the Roman Empire:
Finding any particular piece of information would have been virtually impossible, especially since Roman archivists filed only by year.
The comment appears to come from this book.
Given the longevity, geographic extent and power of the Roman Empire it seems incredible that their bureaucracy could have functioned without the ability to cross reference material in their archives.
Can it really be true that they filed information only by year?