The categorization of the past into discrete, quantified named blocks of time is called periodization. This is a list of such named time periods as defined in various fields of study.
These can be divided broadly into prehistoric periods and historical periods(when written records began to be kept).
Historical regions (or historical areas) are geographical regions which, at some point in history, had a cultural, ethnic, linguistic or political basis, regardless of latter-day borders. There are some historical regions that can be considered as "active", for example: Moravia, which is held by the Czech Republic, is both a recognized part of the country as well as a historical region. They are used as delimitations for studying and analysing social development of period-specific cultures without any reference to contemporary political, economic or social organisations.
Definitions of regions vary, and regions can include macroregions such as Europe, territories of traditional sovereign states or smaller microregional areas. Geographic proximity is generally the required precondition for the emergence of a regional identity. In Europe, regional identities are often derived from the Migration Period but for the contemporary era are also often related to the territorial transformations that followed World War I and those that followed the Cold War.
Historical regions (or historical areas) are geographical regions that had a cultural, ethnic, linguistic or political significance as distinct entities at some point in recorded history, regardless of latter-day borders and administrative divisions. There are some historical regions that can be considered as "active", for example: Moravia, which is held by the Czech Republic, is both a recognized contemporary region of the country as well as a historical one. They are used as delimitations for studying and analysing social development of period-specific cultures without any reference to contemporary political, economic or social organisations.
Definitions of regions vary, and regions can include macroregions such as Europe, territories of traditional sovereign states or smaller microregional areas. Geographic proximity is generally the required precondition for the emergence of a regional identity. In Europe, regional identities are often derived from the Migration Period but for the contemporary era are also often related to the territorial transformations that followed World War I and those that followed the Cold War.
The Serravallian is, in the geologic timescale, an age or a stage in the middle Miocene Epoch/Series, which spans the time between 13.82 Ma and 11.63 Ma (million years ago). The Serravallian follows the Langhian and is followed by the Tortonian.
It overlaps with the middle of the Astaracian European Land Mammal Mega Zone, the upper Barstovian and lower Clarendonian North American Land Mammal Ages and the Laventan and lower Mayoan South American Land Mammal Ages. It is also coeval with the Sarmatian and upper Badenian Stages of the Paratethys time scale of Central and eastern Europe.