I believe that the original Barclay was a Norman compatriot of William The Conqueror, his name was Roger and was granted Berkeley Castle in Gloucestershire, England and so was known as Roger Of Berkeley (or "Roger De Berchelai" in Saxon). His son, John de Berchelai arrived in Scotland in the retinue of Margaret Atheling and was granted Towie Castle near Turiff, Aberdeenshire by Malcolm III by way of gratitude for accompanying Margaret, the Castle was subsequently (as still is) known as "Towie Barclay".