MARY,MARY, QUITE CONTRARY
ORIGINAL RHYME

picture adapted from clipart.com

Mary, Mary quite contrary,

How does your garden grow..

With Silver Bells and cockle shells,

And pretty maids all in a row

Mary Queen of Scots theory:

 
There was always a competition between Mary and Queen Elizabeth; since Mary  was Catholic and Elizabeth Protestant.  Supporters of Elizabeth might have seen her as contrary. Her garden might refer to her realm; Silver Bells might be the bells in the cathedral ,and cockle shells might represent ornamentation. The pretty maids might be her ladies in waiting might be her ladies in waiting. There is absolutely no proof whatsoever that this rhyme refers to Mary Queen of Scots, and any reference to that is legend.

Some legends speculate that contrary Mary was actually Queen Mary I, a Catholic. She might have been seen as contrary to   the wishes of her father, King Henry VIII who dissolved the monasteries. Queen Mary, though married, never had any children,so the reference to the garden might relate to that..how does your garden grow? The pretty maids all in a row might refer to the many people she executed..

The silver bells and cockle shells might have been references to her instruments of torture.

Another theory is that this was a religious related to Catholicism--but even within this legend there is a dispute as to whether the rhyme refers to  the reinstatement or persecution of Catholicism.