The oldest pocket calendar in the world, about 8.000 years old, was found at the archaeological site of Medvednjak, near Smederevska Palanka in Šumadija.

The calendar was made using a wild boar’s tusks. In its outer part there are 28 miniature triangular indentations carved on the inside. This corresponds to a month cycle of 28 days with four distinctive moon phases and suggests that the tusks were used to denote a lunar calendar.