Throughout their lives they remained close friends, and both studied
law at Marburg University.  Jacob was a pioneer in the study of German
philology, and although Wilhelm's work was hampered by poor health the
brothers collaborated in the creation of a German dictionary, not
completed until a century after their deaths.  But they were best (and
universally) known for the collection of over two hundred folk tales
they made from oral sources and published in two volumes of 'Nursery
and Household Tales' in 1812 and 1814.  Although their intention was to
preserve such material as part of German cultural and literary
history, and their collection was first published with scholarly notes
and no illustration, the tales soon came into the possession of young
readers.  This was in part due to Edgar Taylor, who made the first
English translation in 1823, selecting about fifty stories 'with the
amusement of some young friends principally in view.' They have been
an essential ingredient of children's reading ever since. 

End of The Project Gutenberg Etext Fairy Tales, by the Grimm Brothers