Chronograms: dates hidden in the letters of a phrase

A chronogram is a phrase in which certain letters, added up according to their numerical value, give a date. Latin uses Roman numerals: the letters I, V, X, L, C, D and M occurring in the text are written larger or in a different colour, and their sum indicates the year of the event being commemorated. The device was immensely popular in Baroque Europe, but it also has significant parallels in the Jewish and Islamic traditions, based on other numeral alphabets.

A fashion of the Baroque age

Latin chronograms spread above all between the sixteenth and eighteenth centuries, particularly in the German lands and Flanders. They appeared on title pages, coins, medals, bells, tombstones and triumphal arches erected for the entry of sovereigns. On some solemn occasions entire poems were composed in which every line contained the same year, a challenge that required patience and a remarkable command of Latin.

A frequently cited example is linked to King Gustavus II Adolphus of Sweden: ChrIstVs DuX ergo trIVMphVs, “Christ is the leader, therefore triumph”. Adding up the highlighted letters, namely C, I, V, D, X, I, V, M and V, gives 1627. The lower-case u of dux is not counted, because it is deliberately written so as not to appear among the number-letters: it is precisely this graphic choice that guides the reader.

Dates in Hebrew and Arabic

In the Jewish tradition the printing date of a book was often indicated by a word or a biblical verse whose letters, marked with dots or small signs, added up to the year of the Hebrew calendar. The thousands were usually omitted, following the custom known as the “minor reckoning”. Reading these dates correctly is one of the classic difficulties for those who study early Hebrew books, because it is not always clear which letters should be counted.

In the Islamic world the chronogram, based on the values of the abjad, was a refined poetic genre. Persian, Ottoman and Mughal poets closed elegies and celebratory inscriptions with a coded line, and many fountains and mosques in Istanbul still bear inscriptions of this kind above their entrances. For architectural historians they are often the most direct way of dating a building.

Between virtuosity and memory

The chronogram combined two aims: recording a date and turning it into a small puzzle. Its composer had to respect the meaning of the sentence, the grammar and sometimes the metre, while obtaining the exact sum. There was no shortage of critics, who considered these exercises a form of pedantry, but their presence on monuments bears witness to an age's taste for verbal ingenuity and for writing as a learned game.

There are also extreme cases, such as collections made up entirely of chronograms, in which dozens or hundreds of lines repeat the same date to celebrate a jubilee, a coronation or the founding of an institution. These compositions, now almost forgotten, were printed and presented as official tributes, and bear witness to a culture in which Latin was still the common language of Europe's learned elites.

Today many visitors pass a tombstone or a portal without noticing that some letters, larger than the others, contain a year. Recognising a chronogram is a way of reading monuments through the eyes of those who built them, for whom a date could be at once a tribute, a prayer and a display of skill.