Chronology is the science of arranging events in their order of occurrence in time. Consider for example the use of a timeline or sequence of the actual temporal sequence of past events. Chronology is part of periodization. It is also part of the discipline of history including earth history, the earth sciences and study of the geologic time scale. Indian history is a topic of interest to many including foreigners because of the cultures and civilizations existed in this subcontinent. History of India can be studied under political, cultural, religious or economic heads. hronologically Indian history can be classified in to three periods ancient India, medieval India and modern India.