In Songs of Experience Blake introduced the 'forest';
|TIGER, tiger, burning bright|
|In the forests of the night,|
Through the years of his career he used 'forest' often; it occurred 63 times in his poetry.
In his last years he turned to the poetry of Dante and found his 'forest' and put it in one of his Illustrations.
|Dante and Virgil Penetrate the Forest|
"Now go, for both of us have one will; thou guide. thou lord and master,"
Thus I spoke to him,and he proceeding, I entered on the arduous and savage way.
From notes by Milton Klonsky's Blake's Dante:
Page 187: Virgil strides forward with his right foot and flings up his arms like the forks of the oak trees twisting around and directing the poets deeper into the forest.
From Blake's Milton, Plate 25 (Erdman 123):