Vedas
Originally, all the vedas belonged to only one group. Supreme God Narayana has divided the whole group into 4 parts constituting 4 vedas
Later, when the whole vedas were difficult to be sustained in memory and the entire vedic knowledge went topsy turvy due to the curse of Gautama , bhagavAn vedavyAsa, in dvApara yuga, extracted some Rik mantrAs from the R^ig veda and arranged them to form the R^ig veda. He similarly extracted yajur mantrAs from yajur veda amd sama mantrAs from sAma veda etc and instructed them to his four disciples
Different names by which Vedas are called