Historian Mary Beard connects Greek myths and Twitter trolls

For Mary Beard, the image of Hillary Clinton's severed head was the last straw.

The Cambridge University classics professor had been pondering the influence of the ancient world on modern political and public life when she came across mugs and T-shirts bearing an image from Greek mythology: the hero Perseus holding the bloody head of the snake-haired monster Medusa. In this version, Perseus had Donald Trump's face and the monster bore Clinton's.

Beard was shocked both by the brutality of the image and "the domesticity of it. ... The idea that youd be sitting at your breakfast table and youd have a mug with Hillary Clinton being beheaded on it."

Beard asks how that ancient image ended up in a modern political campaign in "Women and Power," a short but punchy book published Tuesday in the US by Liveright.

The book explores the way images and ideas from...