What is the title of Shakespeare's poem a involving the phrase a coward dies a thousand deaths?

It is not in exactly those Words and the phrase does not come from a poem, but from Shakespeare's play Julius Caesar. It is part of a line said by Julius Caesar himself:

"Cowards die many times before their deaths;

The valiant never taste of death but once.

Of all the wonders that I yet have heard.

It seems to me most strange that men should fear;

Seeing that death, a necessary end,

Will come when it will come. "

In other Words, you know you are going to die sooner or later, so why worry about which? You only make yourself suffer.