The theory of the universe was of great importance to Shakespeares contemporaries and was used by him in developing events in his plays. According to this idea:

everything in the world has its position fixed by God
Earth = center of the universe. Stars move around it
God is the head of everything
everything in the world has its order
Society reflected this order with fixed classes from highest to lowest – kings, churchmen, nobles, merchants and peasants.
The animals had their own degrees too, lion = “king”.
Plant life and minerals, too. Among flowers, it was the rose.
Any break in the chain (such as killing the king) ensured chaos
Fate = main controlling force in life. Ups & downs

The Elizabethans called this hierarchical structure The Great Chain of Being