a huge tornado
A historical period, or era as it's sometimes called, is a period of time that is readily identifiable by particular things, events and or persons that happened or existed during that time.
It hasn't happened yet.
big ben was built
Earth is 5.2 billion years old, many things happened, be more specific :)
the historical thing that happened was the Justin bieber concert
The style of the historical period is defined by the movement,school and group.
Facts that happened are historical facts.
what is the historical development of psychology during the ancient period
the romanesque period
stuff happened
The Classical Period.