Isabella Macdonald

Isabella Macdonald (née Clark; 1811 – 28 December 1857) was the first wife of John A. Macdonald, one of the fathers of the Canadian federation. The couple were related by sharing their maternal grandmother; cousin marriage was not uncommon then.
They married in 1843, and during their marriage, he became the premier of the Province of Canada in 1856. She became ill after just two years of marriage, and she developed an addiction to opium mixed with wine (laudanum). She bore two sons: John, who died at 13 months, and Hugh, who grew up to be a politician too.
Her widower went on to become the first post-Confederation Prime Minister of Canada. He remarried to Susan Agnes Bernard in 1867, five months before Canadian Confederation.