A horology calendar system (200) including:—a date wheel (1);—a month cam (300); and—a kinematic connection element (8) arranged so that the date wheel allows the driving of the motion of the month cam. Optionally, the kinematic connection element is arranged so as to allow the driving of the month cam by at most 1/n of a step while the date wheel is driven by one step, where n is a natural integer greater than 1.