In support of this view it may be urged that lines 500-505 of Book i.

wear the appearance of an insertion after the Restoration, and that in the invocation to the Third Book Milton may be thought to allude to the dangers his life and liberty had afterwards encountered, figured by the regions of nether darkness which he had traversed as a poet.
"Hail holy Light!...
Thee I revisit now with bolder wing, Escaped the Stygian pool, though long detained In that obscure sojourn, while in my flight Through utter and through middle darkness borne." The only other passage important in this respect is the famous one from the invocation to the Seventh Book, manifestly describing the poet's condition under the Restoration:-- "Standing on earth, not rapt above the pole, More safe I sing with mortal voice, unchanged To hoarse or mute, though fallen on evil days, On evil days though fallen and evil tongues; In darkness, and with dangers compassed round, And solitude; yet not alone, while thou Visitest my slumbers nightly, or when morn Purples the east.

Still govern thou my song, Urania, and fit audience find, though few.
But drive far off the barbarous dissonance Of Bacchus and his revellers, the race Of that wild rout that tore the Thracian bard." This allusion to the licentiousness of the Restoration literature could hardly have been made until its tendencies had been plainly developed.
At this time "Paradise Lost" was half finished.

("Half yet remains unsung.") The remark permits us to conclude that Milton conceived and executed his poem as a whole, going steadily through it, and not leaving gaps to be supplied at higher or lower levels of inspiration.

There is no evidence of any resort to older material, except in the case of Satan's address to the Sun.
The publication of "Paradise Lost" was impeded like the birth of Hercules.