[1] There he studied classics under Friedrich Gottlieb Welcker who had just returned from a two years' residence in Italy to fill the chair of archaeology and Greek literature.

[2] Next year he returned to his books, and this short taste of military service was the only break in a long and uneventful life of literary labours.

[3] At his parents' desire he applied himself for a short time to law, but a visit to Goethe in 1818 gave a new direction to his studies, and determined his future career.

Goethe had been reading Raynouard's Selections from the Romance Poets, and advised the young scholar to explore the rich mine of Provençal literature which the French savant had opened up.

A great advance was made by Raynouard, who by his critical editions of the works of the Troubadours, published in the first years of the 19th century, laid the foundations on which Diez afterwards built.

The scientific method is to follow implicitly the discovered principles and rules of phonology, and not to swerve a foot's breadth from them unless plain, actual exceptions shall justify it; to follow the genius of the language, and by cross-questioning to elicit its secrets; to gauge each letter and estimate the value which attaches to it in each position; and lastly to possess the true philosophic spirit which is prepared to welcome any new fact, though it may modify or upset the most cherished theory.

To collect and arrange facts is, as he tells us, the sole secret of his success, and he adds in other words the apophthegm of Newton, "hypotheses non fingo".