Historians broadly divide history into different periods or eras based on significant events, changes in societies, and the development of civilizations. These divisions help organize and understand the vast expanse of human history. Here is a detailed explanation of how historians broadly divide history:

1. Prehistoric Era:
- This period refers to the time before written records existed.
- It includes the Paleolithic, Mesolithic, and Neolithic periods when early humans lived as hunter-gatherers and began to settle in communities.
- The prehistoric era encompasses the development of tools, agriculture, and the domestication of animals.

2. Ancient Civilizations:
- This era covers the rise and fall of early civilizations, such as Mesopotamia, ancient Egypt, the Indus Valley, and ancient China.
- These civilizations developed writing systems, complex social structures, and monumental architecture.
- Key events during this period include the invention of writing, the construction of pyramids and temples, and the establishment of legal codes.

3. Classical Era:
- The classical era refers to the time when ancient Greece and Rome flourished.
- It is known for its significant contributions to philosophy, literature, art, and science.
- This period witnessed the rise of democracy in Athens, the conquests of Alexander the Great, and the expansion of the Roman Empire.

4. Medieval Era:
- This era covers the Middle Ages, a period that followed the fall of the Western Roman Empire.
- It includes the Byzantine Empire, the Islamic Golden Age, and feudal societies in Europe.
- The medieval era witnessed the growth of Christianity, the Crusades, the emergence of powerful kingdoms, and the development of Gothic architecture.

5. Early Modern Era:
- This period marks the transition from the Middle Ages to the modern world.
- It includes the Renaissance, the Age of Exploration, the Protestant Reformation, and the Scientific Revolution.
- Key events during this era include the voyages of Christopher Columbus, the printing press, and the works of Leonardo da Vinci and Galileo Galilei.

6. Modern Era:
- The modern era encompasses the industrial revolution, the age of imperialism, the World Wars, and the Cold War.
- It includes significant political, social, and technological changes that shaped the world we live in today.
- Key events during this era include the American and French Revolutions, the invention of the steam engine, the rise of nationalism, and the decolonization of Africa and Asia.

By dividing history into these broad periods, historians can analyze and understand the major transformations and continuities that have occurred throughout human civilization.

Ancient medieval and modern.