Megasthenes was a Greek ambassador to the court of Chandragupta Maurya in the 4th century BCE. He wrote a book called Indica, which provides valuable information about ancient India.

Fa-Hien was a Chinese Buddhist monk who traveled to India in the 5th century CE. He spent six years in India, studying Buddhism and visiting various holy sites.

Hsuan Tsang was a Chinese Buddhist monk who traveled to India in the 7th century CE. He spent 17 years in India, studying Buddhism and visiting various holy sites. His travelogue, called the Great Tang Records on the Western Regions, is a valuable source of information about ancient India.

Al-Biruni was a Persian scholar and traveler who visited India in the 11th century CE. He spent 16 years in India, studying Indian culture, religion, and philosophy. His book, called Kitab al-Hind, is a valuable source of information about ancient India.

Vasco da Gama was a Portuguese explorer who was the first European to sail to India around the Cape of Good Hope in 1498 CE.

François Bernier was a French physician and traveler who visited India in the 17th century CE. He spent 12 years in India, studying Indian culture, religion, and politics. His book, called Travels in the Mughal Empire, is a valuable source of information about Mughal India.

Thomas Roe was an English diplomat and traveler who visited India in the 17th century CE. He was the first English ambassador to the Mughal court. His mission was to negotiate a trade agreement between England and the Mughal Empire.

Max Müller was a German philologist and orientalist who visited India in the 19th century CE. He is best known for his work on the Vedas and other Sanskrit texts. He also made significant contributions to the study of Indian history and culture.

Will Durant was an American historian, philosopher, and writer who visited India in the 20th century CE. He is best known for his book The Story of Civilization, which is a comprehensive history of the world. He also wrote a book called The Case for India, in which he praised Indian culture and civilization.

Vincent Smith was a British historian who wrote a history of India called The Oxford History of India. This book was first published in 1919 and is still considered to be a standard work on Indian history.

Romila Thapar is an Indian historian who is known for her work on ancient India. She has written several books on Indian history, including A History of India, Volume 1, and The Penguin History of Early India.

Bipan Chandra is an Indian historian who is known for his work on modern India. He has written several books on Indian history, including India's Struggle for Independence, and Communalism and the Writing of Indian History.

Irfan Habib is an Indian historian who is known for his work on medieval India. He has written several books on Indian history, including The Agrarian System of Mughal India, and An Atlas of the Mughal Empire.

B.R. Nanda is an Indian historian who is known for his work on the Indian National Congress. He has written several books on Indian history, including The Nehrus: Motilal and Jawaharlal, and Mahatma Gandhi: A Biography.