A calendar stepping mechanism of an eternal calendar of a clock includes a month disk with indentations and elevations corresponding to forty-eight months of a leap year period and a calendar wheel having 31 teeth with one stepping tooth and normal teeth for driving a calendar date display. A stepping lever is pivoted once a day and has a probe finger that rests on the month disk in a normal position of the stepping lever. A connecting link arranged such that, during the pivoting movement of said stepping lever from its normal position into its raised position, a stepping pawl slides along the connecting link, wherein during a first part of the pivoting movement of said stepping lever, the connecting link supports the pawl tooth at a radial distance from an axis of said calendar wheel between the tip circle of the normal teeth and the tip circle of said stepping tooth and, during the second part of the pivoting movement of the shifting lever, the connecting link supports the pawl tooth at a radial distance inward of the tip circle of the normal teeth, wherein a transition from the first part to the second part of the pivoting movement of the stepping lever occurs at the point which the pawl tooth occupies when the stepping lever is in its normal position and the probe finger is in contact with one of the elevations of the stepped month disk.