>>591876
They both share the same mythic imagery, a land of plenty without suffering beyond the reach of normal men.
From Pindar's Pythian Ode:
Never on foot or ship could you find
the marvelous road to the feast of the- Hyperboreans.
Perseus came to them once, a leader of men,
entered their houses,
found them making hecatombs of asses
to Apollo.
Never the Muse is absent
from their ways: lyres clash, and the flutes cry,
and everywhere maiden choruses whirling.
They bind their hair in golden laurel and take their holiday.
Neither disease nor bitter old age is mixed
in their sacred blood; far from labor and battle
they live; they escape Nemesis,
the over just.
>>591879
The four rivers also serve a symbolic purpose, namely the "quartering" of the landscape. The "garden", generally speaking, being an enclosed space. The font of plenty (fons vivus), being the source of the four, emanating from the center.