Renan, educated by priests, was to accept the scientific ideal with an extraordinary expansion of all his faculties. He became ravished by the splendor of the cosmos. The certitudes of physical and natural science were revealed to Renan in 1846 by the chemist Marcellin Berthelot, Renan continued research in Semitic philology and in 1847, he obtained the Volney prize, one of the principal distinctions awarded by the Academy of Inscriptions, for the manuscript of his "General History of Semitic Languages." In 1847, he took his degree as Agrégé de Philosophie – that is to say, fellow of the university – and was offered a job as master in the lycée Vendôme.
Within his lifetime, Renan was best known as the author of the enormously popular Life of Jesus (Vie de Jésus, 1863). The book was first translated into English in the year of its publication by Charles E. Wilbour and has remained in print for the past 145 years.
Renan claimed Jesus was able to purify himself of Jewish traits and that Jesus became an Aryan, his Life of Jesus promoted racial ideas and infused race into theology and the person of Jesus, he depicted Jesus as a Galilean who was transformed from a Jew into a Christian, and that Christianity emerged purified of any Jewish influences. The book was based largely on the Gospel of John, and was a scholarly work. The book's controversial assertions that the Bible could and should be subject to the same critical scrutiny as other historical documents caused some controversy and enraged many Christians.
The fifth and sixth volumes of the Origins of Christianity (the Christian Church and Marcus Aurelius) show him reconciled with democracy, confident in the gradual ascent of man, aware that the greatest catastrophes do not really interrupt the sure if imperceptible progress of the world and reconciled, also, if not with the truths, at least with the moral beauties of Catholicism and with the remembrance of his pious youth.
"What is a Nation?"
Renan's definition of a nation has been extremely influential. This was given in his 1882 discourse Qu'est-ce qu'une nation? ("What is a Nation?"). Whereas German writers like Fichte had defined the nation by objective criteria such as a race or an ethnic group "sharing common characteristics" (language, etc.), Renan defined it by the desire of a people to live together, which he summarized by a famous phrase, "avoir fait de grandes choses ensemble, vouloir en faire encore" (having done great things together and wishing to do more).
Karl Deutsch (in "Nationalism and its alternatives") suggested that a nation is "a group of people united by a mistaken view about the past and a hatred of their neighbors." This phrase is frequently, but mistakenly, attributed to Renan himself. He did indeed write that if "the essential element of a nation is that all its individuals must have many things in common", they "must also have forgotten many things. Renan's work has especially influenced 20th century theorist of nationalism, Benedict Anderson.
He was nearly sixty when, in 1883, he published the autobiographical Souvenirs d'Enfance et de Jeunesse, the work by which he is now best known in France.
Renan was a great worker. At sixty years of age, having finished the Origins of Christianity, he began his History of Israel, based on a lifelong study of the Old Testament and on the Corpus Inscriptionum Semiticarum, published by the Académie des Inscriptions under Renan's direction from the year 1881 till the end of his life. The first volume of the History of Israel appeared in 1887; the third, in 1891; the last two posthumously.
Renan died after a few days' illness in 1892 in Paris.