It had been Domhnall's intention that the marriage would eventually allow the succession of a son, i.e. Donnchadh, but it is probable that Baltar intended to rule in his turn.
In the summer of 1384, King Robert II issued two charters formally conferring the Mormaerdom on Baltar.
However, in 1388, Baltar and Margaret were handed custody of the Mormaerdom for the remainder of their lives, with Donnchadh retaining the title.
In 1425, he raised his men of Lennox in a revolt against King James I in support of Muiredach and his son Walter and was executed at Stirling along with various of his near relations.
During the life of his father Baltar, Donnchadh forged ties with his Argyll neighbours, and married Helen, the daughter of Archibald Campbell of Lochawe.