Chapter 4 Notes: Timeline and Sources of History

History is the study of the human past. We learn about the past through scientists like geologists (study rocks and Earth's physical features), palaeontologists (study fossils), anthropologists (study human societies and cultures), and archaeologists (dig up remains like tools, pots, bones, and toys left behind by people and animals).

The world commonly uses the Gregorian calendar, which counts years forward from the conventional birth year of Jesus Christ as CE (Common Era) and backward as BCE (Before Common Era). Note that there is no year zero — year 1 BCE is immediately followed by year 1 CE. To find the number of years between a BCE and a CE date, add the two numbers and subtract 1 (e.g., Buddha born 560 BCE → years ago in 2024 CE = 560 + 2024 − 1 = 2,583 years). A century = 100 years; a millennium = 1,000 years.

A timeline is a visual tool that arranges historical events in the order they happened, making it easy to see the sequence and duration of events. Important landmarks on a historical timeline include the first rock art (~40,000 BCE), end of the last Ice Age (~12,000 BCE), beginning of agriculture (~10,000 BCE), Indus-Sarasvatī civilisation (~2600–1900 BCE), birth of Buddha (~560 BCE), and many more.

Sources of history are places, persons, texts, or objects that give us information about the past. They are grouped into four main types: Archaeological Sources (excavations, coins, inscriptions, monuments, tools, pottery), Literary Sources (Vedas, Itihasas, travelogues, historical texts, poems), Oral Sources (folklore, genealogical traditions), and Artistic Sources (paintings, sculptures, panels). Historians combine multiple sources — like pieces of a jigsaw puzzle — to reconstruct the past.

Modern humans (Homo sapiens) have existed for about 3,00,000 (three lakh) years. Early humans lived in small groups called bands, sheltered in rock shelters and caves, and survived by hunting animals and gathering edible plants (hence called hunter-gatherers). They used fire, made stone tools and blades, created rock paintings in caves, and wore simple ornaments like shell or stone beads.

After the last Ice Age ended around 12,000 years ago, the climate warmed and early humans began settling near rivers, cultivating cereals, and domesticating animals like cattle and goats — this shift is called the beginning of agriculture. As food supply increased, communities grew into hamlets, then villages, and eventually small towns, developing new technologies like pottery and the use of metals (copper first, then iron).