Breaking history into distinct periods of time is an example of

Periodization

Explanation:

When we break up the past into determinate, quantifiable blocks of time , we then facilitate the approach and analysis of events of history.

The periodization is more or less arbitrary but it has turned the preferred way for grouping events and make descriptions. Usually the abstractions led to difficulties for perciving the greater panoramic view.

The periods that are given, show relatively stable characteristics so they can be put together.

Let's consider the Marxist view of History:  

According to them

   -Primitive communism

   -Slave society

   -Feudalism

   - Capitalism

   - Socialism

As we could go further, we would see that every period given here shows a specific set of characteristics and that the guiding line accounts for mechanisms that have historically accounted for the appearance of socialism.

on the morning of  july 21,  1861, general mcdowell ordered the  unionarmy to attack. it was on this hill that  confederate  colonel thomas jackson and his forces held back theunion  troops.