In 1786 Sir William Jones, a British judge serving in India, made a discovery that transformed knowledge about prehistory and began the formal study of historical linguistics. Turning his spare time towards the study of Sanskrit, the ancient language from which the predominant languages of the South Asian subcontinent derive, Jones discovered that Sanskrit shares features of grammar and vocabulary with Latin and ancient Greek to an extent inexplicable by sheer coincidence. His interest further aroused, he then examined the early Germanic language called “Gothic”, the ancient Celtic languages of Europe, and Old Persian, and found that they, too, exhibited marked similarities to Sanskrit. He concluded that all these languages must have evolved from a common but now-extinct linguistic source. In the early nineteenth century, both this ancient language and the later languages that derived from it, were labelled “Indo-European,” reflecting their wide distribution from India and Ireland.