Question: On what subject did this German-born philologist and Orientalist, who lived in Britain for most of his life and is considered one of the most important German scholars in Indian Philology alongside Heinrich Zimmer, work on?

Context articles: Carl Erdmann
Zeitschrift für celtische Philologie
Fridrik Thordarson
Friedrich Nietzsche
Max Müller
Amiya Prosad Sen
Jean-François Champollion
Dhruv Raina
Heinrich Zimmer
Georgios Hatzidakis

Carl Erdmann (17 November 1898 – 5 March 1945) was a German historian who specialized in medieval political and intellectual history.
 He is noted in particular for his study of the origins of the idea of crusading in medieval Latin Christendom, as well as his work on letter collections and correspondence among secular and ecclesiastical elites in the eleventh century.
 He is often mentioned alongside Percy Ernst Schramm and Ernst H. Kantorowicz as one of the most influential and important German scholars of medieval political culture in the twentieth century.
 His promising and remarkably prolific career was cut short by his death in the German army at the end of World War II.
 His grandson Martin Erdmann is a professor for experimental particle physics at the RWTH Aachen University.
The Zeitschrift für celtische Philologie is an academic journal of Celtic studies, which was established in 1897 by the German scholars Kuno Meyer and Ludwig Christian Stern.
 It was the first journal devoted exclusively to Celtic languages and literature and the oldest significant journal of Celtic studies still in existence today.
 The emphasis is on (early) Irish language and literature and Continental Celtic languages, but other aspects of Celtic philology and literature (including modern literature) also receive attention.
Fridrik Thordarson (1928 – 2 October 2005) was an Icelandic linguist.
 Thordarson was born in Iceland, and studied Classical philology in Oslo.
 In 1963 he took exams with Latin as his major and Greek and Indian philology as his minors.
 From 1965 onwards he taught classical philology as a lecturer and he became professor in 1994.
 He worked for most of his life in Norway.
Friedrich Wilhelm Nietzsche ( ; ] ; 15 October 1844 – 25 August 1900) was a German philosopher, cultural critic, poet, philologist, and Latin and Greek scholar whose work has exerted a profound influence on Western philosophy and modern intellectual history.
 He began his career as a classical philologist before turning to philosophy.
 He became the youngest ever to hold the Chair of Classical Philology at the University of Basel in 1869, at the age of 24.
 He resigned in 1879 due to health problems that plagued him most of his life, and he completed much of his core writing in the following decade.
 In 1889, at age 44, he suffered a collapse and a complete loss of his mental faculties.
 He lived his remaining years in the care of his mother until her death in 1897, and then with his sister Elisabeth Förster-Nietzsche, and died in 1900.
Friedrich Max Müller (6 December 1823 – 28 October 1900), generally known as Max Müller, was a German-born philologist and Orientalist, who lived and studied in Britain for most of his life.
 He was one of the founders of the western academic field of Indian studies and the discipline of comparative religion.
 Müller wrote both scholarly and popular works on the subject of Indology.
 The "Sacred Books of the East", a 50-volume set of English translations, was prepared under his direction.
 He also promoted the idea of a Turanian family of languages.
Amiya Prosad Sen (born 1952) is a historian with an interest in the intellectual and cultural history of modern India.
 Amiya P.Sen currently holds the Heinrich Zimmer Chair at the South Asia Institute, Heidelberg University.
 He has served as Professor of Modern Indian History at Jamia Millia Islamia, New Delhi.
 He has been Agatha Harrison Fellow to the University of Oxford and Visiting Fellow to the Indian Institute of Advanced Study, Shimla, and the Centre for Contemporary Studies, Nehru Memorial Museum & Library, New Delhi.
 During 2007–08, he was Tagore professor at Vishwa Bharati, Shantiniketan.
Jean-François Champollion (Champollion "le jeune"; 23 December 17904 March 1832) was a French scholar, philologist and orientalist, known primarily as the decipherer of Egyptian hieroglyphs and a founding figure in the field of Egyptology.
 A child prodigy in philology, he gave his first public paper on the decipherment of Demotic in 1806, and already as a young man held many posts of honor in scientific circles, and spoke Coptic and Arabic fluently.
 During the early 19th-century French culture experienced a period of 'Egyptomania', brought on by Napoleon's discoveries in Egypt during his campaign there (1797–1801) which also brought to light the trilingual Rosetta Stone.
 Scholars debated the age of Egyptian civilization and the function and nature of hieroglyphic script, which language if any it recorded, and the degree to which the signs were phonetic (representing speech sounds) or ideographic (recording semantic concepts directly).
 Many thought that the script was only used for sacred and ritual functions, and that as such it was unlikely to be decipherable since it was tied to esoteric and philosophical ideas, and did not record historical information.
 The significance of Champollion's decipherment was that he showed these assumptions to be wrong, and made it possible to begin to retrieve many kinds of information recorded by the ancient Egyptians.
Dhruv Raina is a leading Philosopher and Historian of Science from India.
 He is best known for his work on domestication of science in colonial India, transnational intellectual networks of science and historiographies of science.
 Currently he is Professor of History of Science Education at the Zakir Husain Centre for Educational Studies (ZHCES), Jawaharlal Nehru University, New Delhi (2003-).
 He had been a scientist at the National Institute of Science, Technology and Development Studies (NISTADS), New Delhi from 1991 to 2002.
 He was the first Heinrich Zimmer Chair for Indian Philosophy and Intellectual History, Ruprecht-Karls-Universität Heidelberg, Germany (2010–11).
 His basic training is in Physics (MSc Physics, IIT Bombay), and he completed his doctoral studies with Aant Elzinga in Philosophy of Science from the University of Gothenburg, Sweden on the Jesuit enlightenment historiography of Indian Astronomy and Mathematics.
Heinrich Robert Zimmer (6 December 1890 – 20 March 1943) was an Indologist and historian of South Asian art, most known for his works, "Myths and Symbols in Indian Art and Civilization" and "Philosophies of India".
 He was the most important German scholar in Indian Philology after Max Müller (1823-1900).
 In 2010, a "Heinrich Zimmer Chair for Indian Philosophy and Intellectual History" was inaugurated at Heidelberg University.
Georgios Nicolaou Hatzidakis (Greek: Γεώργιος Νικολάου Χατζιδάκις ; 23 November [O.S. 11 November] 1843 , in Myrthios, Ottoman Crete – 28 June 1941, in Athens) was a Greek philologist, who is regarded as the father of linguistics in Greece.
 He was the first chair of Linguistics and Indian Philology at the University of Athens in 1890–1923.