BLAKE & TRADITION

Perhaps early scholars were discouraged from uncovering the Greek and Roman influence on Blake because Blake denied the value of Greek myth and philosophy, seeing that they encouraged a warlike culture. But Kathleen Raine would not be discouraged. She looked at Blake's writing and images and saw reflections of the myths she knew form Homer, Aeschylus, Euripides, Ovid, Apuleius and others.

British Museum
A Bacchic Mystery, copied from d'Hancarville
Figures from a Greek vase

A large part of Volume I of Raine's Blake and Tradition covers the connections between the symbols found in Blake's poetry, and the myths which came down from Greece and Rome. 
These are some titles of chapters in Raine's opus and their subject matter:

The Sea of Time and Space [Porphyry's On the Cave of the Nymphs portrayed in Arlington Tempera]
Thel [As a nymph from Porphyry's On the Cave of the Nymphs]
The Myth of the Kore [The Eleusinian Mysteries influence on Songs of Innocence & of Experience]
Oothoon in Leutha's Vale [The descent of the Soul conceived by Platonists]
Blake's Cupid and Psyche [Metamorphoses by Apuleius influence on Vala and Luvah] 
Emblems of Love [Plato in Phaedrus presents love as mediating between man and Divine]
Gates of Birth and Death [Porphyry's Cave as containing Urthona's Gates]
Specters and Watchers [Plotinus and Descent of the Soul from Enneads portray Souls entering Generation]
A Hermetic Myth [The Divine Pymander of Hermes Trismegistus proposed the descent of light into matter]
Enion [Plotinus conceived that separation of matter and spirit constituted the fall]
Tharmas and the Mental Traveller [In Orphic Mysteries of Dionysus the weakened spiritual principle sought reunification]
 
Raine's goal was to connect Blake's work to the whole tradition of mythopoeic and esoteric thought which was excluded from the rational, materialistic approach of the enlightenment. Greek mythology was just one of the threads she followed to understand the symbolic language of Blake. 

Milton, Plate 1, (E 95)

"The Stolen and Perverted Writings of Homer & Ovid: of Plato &
Cicero. which all Men ought to contemn: are set up by artifice
against the Sublime of the Bible. but when the New Age is at
leisure to Pronounce; all will be set right: & those Grand Works
of the more ancient & consciously & professedly Inspired Men,
will hold their proper rank, & the Daughters of Memory shall
become the Daughters of Inspiration. Shakspeare & Milton were
both curbd by the general malady & infection from the silly Greek
& Latin slaves of the Sword.
...
We do not 
want either Greek or Roman Models if we are but just & true to
our own Imaginations, those Worlds of Eternity in which we shall
live for ever; in Jesus our Lord." 

Works in Illuminated Printing, ON HOMERS POETRY, (E 270)                                        
"Every Poem must necessarily be a perfect Unity, but why Homers is
peculiarly so, I cannot tell
... 
Aristotle says Characters
are either Good or Bad: now Goodness or Badness has nothing to do
with Character
ON VIRGIL                                  
Sacred Truth has pronounced that Greece & Rome as Babylon &
Egypt: so far from being parents of Arts & Sciences as they
pretend: were destroyers of all Art.  Homer Virgil & Ovid confirm
this opinion & make us reverence The Word of God, the only light
of antiquity that remains unperverted by War.  Virgil in the
Eneid Book VI. line 848 says Let others study Art: Rome has
somewhat better to do, namely War & Dominion
  Rome & Greece swept Art into their maw & destroyd it     a
Warlike State never can produce Art.  It will Rob & Plunder &
accumulate into one place, & Translate & Copy & Buy & Sell &
Criticise, but not Make.
  Mathematic Form is Eternal in the Reasoning Memory.  Living
Form is Eternal Existence.
  Grecian is Mathematic Form
  Gothic is Living Form" 

Descriptive Catalogue, (E 536)
"Visions of these eternal principles or characters of human
life appear to poets, in all ages; the Grecian gods were the
ancient Cherubim of Phoenicia; but the Greeks, and since them the
Moderns, have neglected to subdue the gods of Priam.  These Gods
are visions of the eternal attributes, or divine names, which,
when erected into gods, become destructive to humanity.
They ought to be the servants, and not the masters of man, or of
society.  They ought to be made to sacrifice to Man, and not man
compelled to sacrifice to them; for when separated from man or
humanity, who is Jesus the Saviour, the vine of eternity, they
are thieves and rebels, they are destroyers."

Jerusalem, Plate 98, (E 258)

"Where is the Covenant of Priam, the Moral Virtues of the Heathen
Where is the Tree of Good & Evil that rooted beneath the cruel heel
Of Albions Spectre the Patriarch Druid! where are all his Human Sacrifices
For Sin in War & in the Druid Temples of the Accuser of Sin: beneath
The Oak Groves of Albion that coverd the whole Earth beneath his Spectre
Where are the Kingdoms of the World & all their glory that grew on Desolation"

.