Identify the source of this metaphor.
"All the world's a stage, and all the men and women merely players."
The source of this metaphor is William Shakespeare's play "As You Like It," in which the character Jaques speaks these lines in a monologue.
Complete the following task based on the instruction and optional input provided.### Instruction:
Identify the source of this metaphor.

### Input:
"All the world's a stage, and all the men and women merely players."

### Output:
The source of this metaphor is William Shakespeare's play "As You Like It," in which the character Jaques speaks these lines in a monologue.