Likely middle-aged, the widowed 9th century Mercian Queen Ælfflæd attracted a suitor, but there was one problem. Her son Wigstan, who gave up the throne for a religious life, forbid the marriage because of consanguinity—that she and the wannabe bridegroom were too closely related. Or Wigstan persuaded his mom to refuse the offer for that reason. Wigstan paid a high price as a result.
The story got me wondering about Ælfflæd and her circumstances and inspired a blog post on English Historical Fiction Authors.