In this handout official photograph provided by Buckingham Palace to mark her 90th birthday, shows Queen Elizabeth II with her five great-grandchildren and her two youngest grandchildren. The children are: James, Viscount Severn (left), 8, and Lady Louise (second left), 12, the children of The Earl and Countess of Wessex; Mia Tindall (holding The Queen’s handbag), the two year-old-daughter of Zara and Mike Tindall; Savannah (third right), 5, and Isla Phillips (right), 3, daughters of The Queen’s eldest grandson Peter Phillips and his wife Autumn; Prince George (second right), 2, and in The Queen’s arms and in the tradition of Royal portraiture, the youngest great-grandchild, Princess Charlotte (11 months), children of The Duke and Duchess of Cambridge. Photograph Annie Leibovitz via Getty Images

Monarchs do things differently. Should their birthday fall in a chilly month, for example, they are free to declare another, sunnier date. So while Qu(...)