Mary Queen of Scots
Shakespeare being under the patronage of Queen Elizabeth, and knowing her jealousy, would not, of course, praise openly her rival queen; but in the Midsummer Night's Dream, composed in 1592, that is, five years after the execution of Mary, he wrote these exquisite lines:
Thou rememberest Since once I sat upon a promontory, And heard a mermaid (1) on a dolphin's back (2) Uttering such dulcet and harmonious breath, That the rude sea (3) grew civil at her song; And certain stars (4) shot madly from their spheres (5), To hear the sea-maid's music.
Act ii. 1.
(1) Mermaid and sea-maid, that is, Mary: (2) on the dolphin's back, she married the Dolphin or Dauphin of France; (3) the rude sea grew civil, the Scotch rebels; (4) certain stars, the Earl of Northumberland, the Earl of Westmoreland, and the Duke of Norfolk; (5) shot madly from their spheres, that is, revolted from Queen Elizabeth, bewitched by the sea-maid's sweetness.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
More on Mary Queen of Scots from Infoplease: