"When I have Fears that I may Cease to Be" is an Elizabethan sonnet by the English Romantic poet John Keats. The 14-line poem is written in iambic pentameter and consists of three quatrains and a couplet. Keats wrote the poem in 1818. It was published (posthumously) in 1848.
The Text 
When I have fears that I may cease to be
Before my pen has gleaned my teeming brain,
Before high-piled books, in charact'ry,
Hold like rich garners the full-ripen'd grain;
When I behold, upon the night's starr'd face,
Huge cloudy symbols of a high romance,
And think that I may never live to trace
Their shadows, with the magic hand of chance;
And when I feel, fair creature of an hour!
That I shall never look upon thee more,
Never have relish in the faery power
Of unreflecting love!—then on the shore
Of the wide world I stand alone, and think
Till Love and Fame to nothingness do sink.