Description
On the title page of most older Hebrew books, the year of publication is given through a chronogram. This distinctive convention is enabled by the dual function of the Hebrew alphabet, which serves as both letters and numbers. The chronogram is hidden in a phrase taken from the Bible or some other holy text. To get the date, you add up the numerical value of letters highlighted in various ways.
This example is taken from a book of rules for a Ḥevra Ḳadisha, a Jewish burial society. One panel on the title page has the quotation "lift up your heads, O gates" from Psalm 24. This is appropriate to burial of the dead since, in traditional Jewish interpretation, the verse refers to the gates of heaven.
The last word, “your heads,” is written larger than the others, which indicates that this word contains the chronogram. The numerical value of those letters adds up to 571, so the book was published in the Jewish year 5571, which starts in the fall of 1810 (chronograms omit the thousand, considering only לפ״ק = לפרט קטן, "the minor era")