Chardin had noted the use of two different calendars in Persia, lunar and solar. Montesquieu in this novel uses lunar months, no doubt because they “are the common months of all Muhammadams, for both spiritual and civil purposes” (Chardin, V, 116-118). But he makes them correspond to the months of the European solar calendar, as Robert Shackleton showed in a definitive article on the subject. [1] We therefore reproduce the table which Shackleton drew up, adding the names used by Chardin.