James mill a Scottish Historian thought that Indian history is very big and if we sort them together there would be a mess.So he divided our history into 3 periods in his book: The history of British India.
HINDU - (Ancient India).
MUSLIM - (medieval India).
BRITISH - (Modern India).

This was his assumption of dividing history into 3 periods.
I hope that this will help you to your question!
go ahead!!

Dividing the Past into Periods
Historians divide the past into periods based on significant events, cultural shifts, technological advancements, and social changes. This categorization helps in understanding and analyzing history in a more structured and organized manner.

Key Factors in Dividing History into Periods
- **Political Events:** Major political events such as wars, revolutions, and changes in government can mark the beginning or end of a historical period. For example, the French Revolution marked the end of the Enlightenment period and the beginning of the Romantic era.
- **Cultural Movements:** Cultural movements like the Renaissance, Industrial Revolution, and the Civil Rights Movement have had a profound impact on society and can define a specific period in history.
- **Technological Advancements:** The development of new technologies has often revolutionized societies and economies, leading historians to designate certain periods based on technological milestones like the Industrial Revolution or the Information Age.
- **Social Changes:** Shifts in social structures, demographics, and norms can also play a role in dividing history into periods. For instance, the transition from feudalism to capitalism marked a significant shift in societal organization.

Examples of Historical Periods
- **Ancient Period:** Includes civilizations like Ancient Egypt, Mesopotamia, and the Greek and Roman empires.
- **Medieval Period:** Characterized by feudalism, the rise of Christianity, and the Crusades.
- **Modern Period:** Begins with the Renaissance and includes the Industrial Revolution, World Wars, and globalization.
- **Contemporary Period:** Encompasses recent events like the Cold War, the digital revolution, and globalization.
By categorizing history into periods, historians can better analyze and interpret the past, identifying trends, causes, and effects that have shaped the world we live in today.