Patrick Maclellan of Bombie
By marriage to his cousin , Margaret Douglas ( daughter of Archibald Douglas , 5th Earl of Douglas ) William Douglas , a member of the 'Black Douglas' family thereby increased the powers vested in his family and estates to the point where he was the most powerful nobleman in the country . 
<triplet> Margaret Douglas <subj> Archibald Douglas, 5th Earl of Douglas <obj> father <triplet> Archibald Douglas, 5th Earl of Douglas <subj> Margaret Douglas <obj> child