Social Sciences: Class 6 — Chapter 4: Timeline and Sources of History

The Gregorian calendar is the most common calendar used worldwide today. It features 12 months (365 days, with a leap year every four years, except centenary years unless they are multiples of 400).

• Common Era (CE): Formerly marked as AD (Anno Domini), counting forward from the conventional birth year of Jesus Christ.
• Before Common Era (BCE): Formerly marked as BC (Before Christ), counting backward from the birth of Jesus Christ.

Calculating Time Intervals: Because there is no "year zero" in the Gregorian calendar (1 CE immediately follows 1 BCE), calculating the years between a BCE date and a CE date requires adding the two years and subtracting 1:

$$\text{Years elapsed} = \text{BCE year} + \text{CE year} - 1$$

For example, if Gautama Buddha was born in 560 BCE, his birth in relation to the year 2024 CE is calculated as: $560 + 2024 - 1 = 2583$ years ago.

• Century: A period of 100 years. Centuries are counted starting from 1 CE (e.g., the 21st century CE runs from 2001 to 2100).
• Millennium: A period of 1,000 years (e.g., the 3rd millennium CE runs from 2001 to 3000).
• Pañchānga: A traditional Indian calendar book of tables relying on the positions of the sun and moon to define months, predict astronomical events (eclipses, sunrise/sunset), weather, and festivals.

• Archaeological Sources:
  • Structures: Monuments, mounds.
  • Excavations: Human, animal, and plant remains; tools and weapons; figurines and ornaments; pottery and toys; habitations and burials.
  • Inscriptions: Manuscripts, copper plates, coins.
• Literary Sources:
  • Indian Literature: Vedas and Itihasas, poems and plays, historical texts, collections of stories, scientific and technological texts.
  • Foreign Accounts: Travelogues, historical chronicles.
• Oral Sources: Genealogical records, folklore.
• Artistic Sources: Paintings, sculptures, panels.

Historians study and write about the past by gathering and cross-verifying information from multiple sources. When sources contradict, they must evaluate which is more reliable. Modern historical reconstruction also relies on scientific fields like genetics (the study of inherited characteristics) and climate studies.

The last Ice Age (a cold period when much of the Earth was covered in ice) lasted from over 100,000 years ago to about 12,000 years ago. As the climate warmed, humans began settling down, cultivating cereals/grains, and domesticating animals (cattle, goats).

• Settlements: Early agricultural communities settled near fertile river valleys. Hamlets (small villages) grew into larger villages and eventually small towns.
• Social Structure: Chieftains or leaders managed community welfare. Land was sowed and harvested collectively, with no initial concept of individual ownership.
• New Technologies: Development of pottery for storage and the introduction of metallurgy (using copper first, and iron later) to create durable tools and ornaments.