The dagger has always been a mark of judgement, and its judgements have never been kind. It belongs to the obelus family, the ancient editors' set of marks for flagging text they doubted. In the hands of early scholars, the dagger meant that a passage was spurious, a line to be regarded with suspicion, questioned, or cut altogether. To place the mark beside a sentence was to cast a shadow over it, to say that this might not belong, that a later reader would be wise to weigh it carefully or leave it out. It is, in its origin, the punctuation of distrust.

Over the centuries the dagger found a steadier and less severe occupation. It became the standard second footnote mark, the symbol that follows the asterisk when a page needs more than one note. Where the little star takes the first footnote, the dagger takes the second, a quiet partnership that has organised the margins of scholarly pages for generations. In this role its old sense of doubt softens into mere sequence; it is simply the next mark in line, pointing the reader to the second aside without accusing the text of anything.

But the dagger's most affecting duty is the one it kept from its grave beginnings. Placed before a name or a year, the mark means that a person has died. In a list of contributors, a genealogy, or a printed programme, the small cross beside a name tells you gently that this person is no longer living, the date beside it the year of their death. It is a usage of great tact, saying in one silent character what words would make heavier. The exhibit is drawn to this arc: a mark that began by condemning text as doubtful or best cut has become, at its most human, the sign we use to note that someone is gone. From flagging what should be removed from a manuscript to marking who has departed from the world, the dagger has always pointed, in its grave way, at absence.