How art thou fallen from heaven, O Lucifer, son of the morning! how art thou cut down to the ground which didst weaken the nations!

Tertullian and Gregory the Great understood this passage of Isaiah in reference to the fall of Satan; in consequence of which the name Lucifer has since been applied to Satan.

How wretched
Is that poor man that hangs on princes' favors! . . .
When he falls, he falls like Lucifer,
Never to hope again.