sentences:  When Thomas Douglas began buying into the Hudson's Bay Company, he followed suit, and by 1810 was on the HBC Board.As a brother-in-law, he was associated with his establishment of the Red River Colony, in Canada, and on the death of the former, he took over the trust, as a trustee of the 5th Earl of Selkirk Estate.As a Member of the London Committee of the Hudson's Bay Company, he was instrumental in bringing about the Union with the North West Company in 1821, the principal opponent to the Selkirk settlement in the Red River Colony.