Analysis of Scorn Not the Sonnet

Scorn not the Sonnet; Critic, you have frowned,
Mindless of its just honours; with this key
Shakspeare unlocked his heart; the melody
Of this small lute gave ease to Petrarch's wound;
A thousand times this pipe did Tasso sound;
With it Camoens soothed an exile's grief;
The Sonnet glittered a gay myrtle leaf
Amid the cypress with which Dante crowned
His visionary brow: a glow-worm lamp,
It cheered mild Spenser, called from Faery-land
To struggle through dark ways; and when a damp
Fell round the path of Milton, in his hand
The Thing became a trumpet; whence he blew
Soul-animating strains--alas, too few!