What 14 line poem did william Shakespeare right?

The poem you are referring to is a sonnet. William Shakespeare wrote 154 sonnets, which are known for their lyrical beauty and exploration of themes such as love, beauty, mortality, and the passage of time. Each sonnet consists of 14 lines, typically written in iambic pentameter (a specific rhythmic pattern).

Here is an example of one of Shakespeare's sonnets, Sonnet 18:

Shall I compare thee to a summer's day?

Thou art more lovely and more temperate:

Rough winds do shake the darling buds of May,

And summer's lease hath all too short a date:

Sometime too hot the eye of heaven shines,

And often is his gold complexion dimmed;

And every fair from fair sometime declines,

By chance, or nature's changing course, untrimmed;

But thy eternal summer shall not fade

Nor lose possession of that fair thou ow'st,

Nor shall Death brag thou wander'st in his shade,

When in eternal lines to time thou grow'st,

So long as men can breathe or eyes can see,

So long lives this, and this gives life to thee.

In this sonnet, Shakespeare compares the beauty of his beloved to that of a summer day. However, he argues that his beloved is more beautiful because summer can be fleeting and subject to change, while his beloved's beauty is eternal and will never fade. The sonnet ends with the famous lines "So long as men can breathe or eyes can see, So long lives this, and this gives life to thee," expressing the idea that the beloved's beauty will live on forever through the power of poetry.