The Deceased Wife's Sister's Marriage Act 1907 was a statute passed by the Parliament of the United Kingdom.
Previously, it was forbidden for a man to marry the sister of his deceased wife. This prohibition derived from a doctrine of Canon Law whereby those who were connected by marriage were regarded as being related to each other in a way which made marriage between them improper. This doctrine was reflected in the Table of kindred and affinity in the British Book of Common Prayer. Prohibition of marriage between certain degrees of kindred outlawed what is known as incest; prohibition between degrees of relationship by marriage (affinity) as opposed to blood (consanguinity) seems to have reflected an analogous taboo. At least one novel, Felicia Skene's The Inheritance of Evil; Or, the Consequences of Marrying a Deceased Wife's Sister addressed the topic in polemic fictional form.

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