His father, Philipp Grimm, was a lawyer who died while Jacob was a child, and his mother Dorothea was left with a very small income.

It was in Savigny's library that Grimm first saw Bodmer's edition of the Middle High German minnesingers and other early texts, which gave him a desire to study their language.

He complained that he had to exchange his stylish Paris suit for a stiff uniform and pigtail, but the role gave him spare time for the pursuit of his studies.

[4] In 1808, soon after the death of his mother, he was appointed superintendent of the private library of Jérôme Bonaparte, King of Westphalia, into which Hesse-Kassel had been incorporated by Napoleon.

In 1813, after the expulsion of Bonaparte and the reinstatement of an elector, Grimm was appointed Secretary of Legation accompanying the Hessian minister to the headquarters of the allied army.

Jacob Grimm lectured on legal antiquities, historical grammar, literary history, and diplomatics, explained Old German poems, and commented on the Germania of Tacitus.

[4] Grimm joined other academics, known as the Göttingen Seven, who signed a protest against the King of Hanover's abrogation of the liberal constitution which had been established some years before.

They remained there until 1840 when they accepted King Frederick William IV's invitation to move to the University of Berlin, where they both received professorships and were elected members of the Academy of Sciences.

He describes his own work at the end of his autobiography: Nearly all my labours have been devoted, either directly or indirectly, to the investigation of our earlier language, poetry and laws.

My principle has always been in these investigations to under-value nothing, but to utilize the small for the illustration of the great, the popular tradition for the elucidation of the written monuments.

He drew on the work of past generations, from the humanists onwards, consulting an enormous collection of materials in the form of text editions, dictionaries, and grammars, mostly uncritical and unreliable.

Some work had been done in the way of comparison and determination of general laws, and the concept of a comparative Germanic grammar had been grasped by the Englishman George Hickes by the beginning of the 18th century, in his Thesaurus.

Grimm had concluded that all philology must be based on rigorous adherence to the laws of sound change, and he subsequently never deviated from this principle.

The Grammar is noted for its comprehensiveness, method and fullness of detail, with all his points illustrated by an almost exhaustive mass of material, and it has served as a model for all succeeding investigators.

[4] Jacob is recognized for enunciating Grimm's law, the Germanic Sound Shift, which was first observed by the Danish philologist Rasmus Christian Rask.

The correspondence of single consonants had been more or less clearly recognized by several of his predecessors, including Friedrich von Schlegel, Rasmus Christian Rask and Johan Ihre, the last having established a considerable number of literarum permutationes, such as b for f, with the examples bœra = ferre ("to bear"), befwer = fibra ("fiber").

A current project at the Berlin-Brandenburg Academy of Sciences and Humanities is underway to update the Deutsches Wörterbuch to modern academic standards.

Volumes A–F were planned for completion in 2012 by the Language Research Centre at the Berlin-Brandenburg Academy of Sciences and Humanities and the University of Göttingen.

Yet even in this essay, Grimm showed that Minnesang and Meistergesang were really one form of poetry, of which they merely represented different stages of development, and also announced his important discovery of the invariable division of the Lied into three strophic parts.

He therefore left this department to others, especially Lachmann, who soon turned his brilliant critical genius, trained in the severe school of classical philology, to Old and Middle High German poetry and metre.

The closely related subject of the satirical beast epic of the Middle Ages also held great charm for Jacob Grimm, and he published an edition of the Reinhart Fuchs in 1834.

This work covered the whole range of the subject, attempting to trace the mythology and superstitions of the old Teutons back to the very dawn of direct evidence, and following their evolution to modern-day popular traditions, tales, and expressions.

Grimm's Weisthümer (4 vol., 1840–63), a compilation of partially oral legal traditions from rural Germany, allows research of the development of written law in Northern Europe.

He wished for a united Germany, and, like his brother, supported the Liberal movement for a constitutional monarchy and civil liberties, as demonstrated by their involvement in the Göttingen Seven protest.