Who invented the calendar and how were they invented?

This question is not very specific on a number of levels. Does this question mean the calendars that we use today? There are a number of different calendars used in different parts of the world. Does it mean the first lunar or solar calendar? For this answer, we should just focus on who invented a calendar in general.  

Many would point to the calendars used by the Sumerians and Egyptians for planting as the earliest calendars. The Chinese used calendars early in their history and the Mayan calendar is touted for its extreme accuracy. Despite all of these ancient civilizations using calendars, none of them can be considered the "inventor" of the calendar. According to the archaeological record, the earliest calendars were used in Europe and date back to 32,000 BC. Paleolithic man utilized a lunar calendar. They would track the moon and used bones to record the phases of the moon. They used bones or small rocks because they were nomadic and needed to take the calendars with them from place to place.