Isabella Clark (1811-1857) was the first wife of John A. Macdonald, the premier of the Province of Canada in 1856 (after Clark's death he went on to become the first post-Confederation Prime Minister of Canada). She was his second-cousin; they had a maternal great grandmother in common. She became ill after just two years marriage in 1845 and died of unknown causes after 13 years of misfortunate marriage, set mostly in sickrooms. Wikipedia
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