Growing up royal: How Elizabeth and Margaret's close bond was tested by a 'forbidden' love

The two siblings were as different as night and day. As such, it would have been understandable if princesses Elizabeth and Margaret had never seen eye to eye. During childhood, the future Queen was "a jolly little girl, but fundamentally sensible and well-behaved," in the words of cousin Margaret Rhodes, while her younger sister was "the naughty one. She was always more larky."

Indeed, as an adult, Princess Margaret famously declared: "Disobedience is my joy."

TAP TO LEARN MORE ABOUT THE QUEEN AND MARGARET'S RELATIONSHIP: Elizabeth was the obedient one while her sister preferred to be carefree

Yes, even with their polar-opposite personalities, the sisters developed an unbreakable bond. Theirs was a connection that would be tested many times - espeecially once the Queen ascended the throne and duty had to come before all else.

Click through our gallery to learn more about the sisters' iron-clad relationship and the 'forbidden' love that tested their bond...