Sir William Jones

1786 is the year wich many people regard as the birthdate of linguistics. On the 27th of September, 1786, an Englishman, Sir William Jones, read a paper to the Royal Asiatic Society in Calcutta pointing out that Sanskrit, Greek, Latin, Celtic and Germanic all had striking structural similarities. So impressive were these likenesses that these languages must spring from one common source, he concluded.
Sir William Jones' discovery fired the imagination of scholars. For the next hundred years, all other linguistic work was eclipsed by the general preoccupation with writing comparative grammars, grammars which first compared the different linguistic forms he found in the various members of the Indo-European language family, and second, attempted to set up a hypothetical  ancestor, Proto-Indo-European, from which all these languages were descended.