diaitia, material goods such as houses and consumables; ethea, the mores or customs; and nomoi, the authoritative precedents or laws. Tacitus The Roman historian, Tacitus, wrote many of our only surviving contemporary accounts of several ancient Celtic and Germanic peoples. Middle Ages Another candidate for one of the first scholars to carry out comparative ethnographic-type studies in person was the medieval Persian scholar Abu Rayhan al-Biruni of the Islamic Golden Age, who wrote about the peoples, customs, and religions of the Indian subcontinent. According to Akbar S. Ahmed, like modern anthropologists, he engaged in extensive participant observation with a given group of people, learnt their language and studied their primary texts, and presented his findings with objectivity and neutrality using cross-cultural comparisons. Others argue, however, that he hardly can be considered an anthropologist in the conventional sense. He wrote detailed comparative studies on the religions and cultures in the Middle East, Mediterranean, and especially South Asia. Biruni's tradition of comparative cross-cultural study continued in the Muslim world through to Ibn Khaldun's work in the fourteenth century. Medieval scholars may be considered forerunners of modern anthropology as well, insofar as they conducted or wrote detailed studies of the customs of peoples considered "different" from themselves in terms of geography. John of Plano Carpini reported of his stay among the Mongols. His report was unusual in its detailed depiction of a non-European culture. Marco Polo's systematic observations of nature, anthropology, and geography are another example of studying human variation across space. Polo's travels took him across such a diverse human landscape and his accounts of the peoples he met as he journeyed were so detailed that they earned for Polo the name "the father of modern anthropology". Renaissance The first use of the term "anthropology" in English to refer to a natural science of humanity was apparently in Richard Harvey's 1593 Philadelphus, a defense of the legend of Brutus in British history, which, includes the passage: "Genealogy or issue which they had, Artes which they studied, Actes which they did. This part of History is named Anthropology." The Enlightenment roots of the discipline Many scholars consider modern anthropology as an outgrowth of the Age of Enlightenment (1715–89), a period when Europeans attempted to study human behavior systematically, the known varieties of which had been increasing since the fifteenth century as a result of the first European colonization wave. The traditions of jurisprudence,