Lord of the Isles Angus Og MacDonald & Agnes O'Cathan 
They had a son named Dubh.
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Children
Lord of the Isles John (Dubh) MacDonald
John, known as Dubh, was born in 1300 in Scotland.1 He died at the age of 87 in 1387 in Artomish, Morven, Argyllshire, Scotland. He was buried in Iona, Mull, Argyllshire, Scotland.2 1
1 http://wc.rootsweb.ancestry.com/cgi-bin/igm.cgi?op=PED&db=bevangenealogy&id=I34272&style=TABLE
2 http://wc.rootsweb.ancestry.com/cgi-bin/igm.cgi?op=GET&db=bevangenealogy&id=I71044
2 http://wc.rootsweb.ancestry.com/cgi-bin/igm.cgi?op=GET&db=bevangenealogy&id=I71044