What two disciples had their mother ask Jesus for the right sit at his left hand and right hand in heaven?

In Mark 10:35-37, James and John, 'sons of thunder', asked Jesus that he let them sit on his right and left hand in heaven. When copying from Mark, the author of Matthewaltered this (Matthew 20:20-21) so that it was their mother who made this request, perhaps to avoid the appearance of presumption on the parts of two important disciples.