The span of recorded history is roughly 5,000 years, beginning with the Sumerian cuneiform script, with the oldest coherent texts from about 2600 BC. Ancient history covers all continents inhabited by humans in the period 3000 BC – AD 500.

The broad term "ancient history" is not to be confused with "classical antiquity". The term classical antiquity is often used to refer to Western history in the Ancient Mediterranean from the beginning of recorded Greek history in 776 BC (first Olympiad). This roughly coincides with the traditional date of the founding of Rome in 753 BC, the beginning of the history of ancient Rome, and the beginning of the Archaic period in Ancient Greece.

The academic term "history" is not to be confused with colloquial references to times past. History is fundamentally the study of the past, and can be either scientific (archaeology, with the examination of physical evidence) or humanistic (the study of history through texts, poetry, and linguistics).During the time period of ancient history (starting roughly from 3000 BC), the world population was already exponentially increasing due to the Neolithic Revolution, which was in full progress. According to HYDE estimates from the Netherlands, world population increased exponentially in this period. In 10,000 BC in prehistory, the world population had stood at 2 million, rising to 45 million by 3,000 BC. By the rise of the Iron Age in 1,000 BC, the population had risen to 72 million. By the end of the period in 500 AD, the world population is thought to have stood at 209 million. In 3,500 years, the world population increased by 100 times.