Final answer:
Thucydides is considered by many historians to be the greatest historian of the ancient world due to his rigorous and objective analysis in the 'History of the Peloponnesian War'. Sima Qian holds a similar status in Chinese history as the 'Father of Chinese History'.
Step-by-step explanation:
Many historians regard Thucydides as the greatest historian of the ancient world. Thucydides, an Athenian historian who lived from 460 to 404 BCE, is often referred to as the "father" of historical writing. He is best known for his work 'History of the Peloponnesian War', where he demonstrated methodical storytelling and in-depth analysis of the human motivations and decisions that led to the events of the war. Thucydides and Herodotus are seen as the first true historians because they sought to employ a rational, evidence-based approach to explain causes and effects of human actions. Herodotus, often named the "Father of History", was the founding figure of Greek historical writing with significant contributions, including his work on the history of the Persian War. Nevertheless, it is the rigor and objectivity of Thucydides in his analyses that yield many to consider him the greatest historian.
Regarding Chinese history, Sima Qian is often viewed as the "Father of Chinese History".