Yes, there have been instances in history where kings married their sisters. One such example is found in ancient Egypt. Senwosret I, who reigned around 1961 B.C. to 1917 B.C., was married to his sister Neferu. Another Egyptian ruler, Amenhotep I, who reigned approximately from 1525 B.C. to 1504 B.C., was also married to his sister Ahmose-Meritamun. Additionally, Cleopatra VII, who reigned from around 51 B.C. to 30 B.C., also married her sibling. These marriages between siblings were not uncommon in ancient Egyptian royalty, as they were seen as a way of maintaining the purity of the royal bloodline. However, it should be noted that sibling marriages in royal families were not exclusive to Egypt and have occurred in various other cultures and time periods as well.
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