The mathematician Jacques Français (1775-1833) had the following to say regarding Servois' perpetual calendar:
The examination of the ingenious table of triple entries given in this volume (page 84) by Mr. Servois engaged me to review, in the Correspondance astronomique et géographique of Mr. the Baron Zach (August 1800), the article of Mr. Gauss which gave him the idea, and where this illustrious geometer learned to find, without epoch, golden number, or dominical letter, the date of the Feast of Easter, for any year and present thusly, in two pages, all of the theory of the calendar, whether Julian or Gregorian [Français, p. 273].
Interestingly, Français extended this compliment two months after Servois publically stated in the pages of the Annales that “I had long thought of calling the ideas of Messrs. Argand and Français on complex numbers by the odious qualifications of useless and erroneous ..." [Servois 1814a, p. 228]. If Français had read Servois’ harsh criticism of his work before he submitted this letter, then we may conclude that Français was definitely a thick-skinned gentleman.
In summary, François-Joseph Servois was a man with a variety of mathematical talents ranging from geometry to calculus, who in 1813 added the workings of the calendar to his mathematical repertoire. Servois' calendar may not be considered ground breaking in the field of mathematics; however, Bradley may have said it best when he wrote that the calendar is “clever, and efficiently manages a large quantity of information in a small space ....” [Bradley, p. 11].