Mabel became interested in unicorns when she was making an alphabet book with Daddy recently, and came upon a unicorn picture for the letter U. It didn't take any more than that, at age four, to set her off on the traditional American-girl infatuation with unicorns. She included it in her alphabet book and Daddy printed her a big version, at her request, to tape on her wall. She showed it to me (not for the first time) when I visited her on Sunday. When I came home one of the first images I discovered in my ongoing delving into the recesses of the digitized Royal Collection was – of course – a drawing of a unicorn made by Roman artist Pier Francesco Mola in the 1630s. As tradition dictates, the unicorn discovers a beautiful virgin and pays homage.