A lack of historical knowledge is easily exploited in the fractious world of social media.
Every day appears to have become a National or International Day of something or other. Take 27 January. In addition to being the Feast of St Angela Merici, founder of Christendom’s first teaching congregation of women, it is now, apparently, National Chocolate Cake Day. To celebrate, Jonathan Healey, a mischievous young Oxford historian, offered the following post on social media: