What was the goal of the Grimm brothers book of fairy tales?

With the usual Teutonic zeal (Ziel) for detail the Brothers Grimm- who were lexicographers and authors of reference books- like Webster,set out to trace the origin and connections between various (hausMarchen) Literally house-marches you cn"t really translate it but household tales or legends comes close) and observe similarities and differences between them in a scientific study of folklore. Grimm was also responsible for Grimm"s law in linguistics, so these were serious bros here!