Scotland and England have been frenemies for centuries as Mary Queen of Scots knew well. Mary became Queen of Scotland as a babe and was next in line for the English throne after her older cousin Elizabeth I. Elizabeth, however, refused to acknowledge Mary as her heiress and was threatened by the Roman Catholics who saw Mary as the true queen. So when Mary foolishly ran to Elizabeth for help, following some poor political and personal decisions, the ever cunning Elizabeth did not come to her aid. Instead she had her cousin locked away for the next 18 years of her life and, after an assassination plot was revealed, ordered Mary's execution at the age of 44. Thankfully, beheadings don't factor into most family rivalries these days.