Lower, Mark A (1860) Patronymica Britannica: a dictionary of the family names of the United Kingdom. London: J.R. Smith. Public Domain.
BROTHER
As described in historical dictionaries
Patronymica Britannica (1860)
BROTHER. Apparently not from the relation of kindred, but from a baptismal name. There was a Danish king so called, as also one of the Scandinavian kings of Dublin. In Germany the corresponding name of Bruder is foimd. Two Danish nobles at tlie Court of Canute also bore the name. Ferguson. The forms in Domesd. are Broder, Brodre, kc, and in the H.R. Brother and Le Brother. Hence Brothers, Brotherson, and the local Brotherton.