The title "Let There Be Light" is a biblical phrase from Genesis 1:3. The Latin translation is "fiat lux". Kevin Sorbo later starred in the Christian drama film Let There Be Light (2017).
Zarathustra, called Zoroaster by the Greeks, was a Persian prophet who founded a still-extant monotheist religion. He is known in popular culture as the basis for Friedrich Nietzsche's play "Also sprach Zarathustra," and Richard Strauss' same-named musical opus, aka the 2001: A Space Odyssey (1968) theme. Zarathustra's traditional biographies place his life anywhere between 1500 and 500 BC, which may be the basis for this story's conceit that he was cursed by Dahak to live 1000 years.
At 33:06 Hercules says "That's one giant leap for mankind". This is the exact phrase spoken by NASA astronaut Neil Armstrong as he became the first human to set foot on the Moon.
At 34:26 Hercules invents pole vaulting.
In a humorous anachronism to break up the grim tension, at 35:36 Iolaus/Dahak leads a gospel choir as he speaks with the accent of a Southern evangelist. The then-recent Disney cartoon Hercules (1997) used similar music as its theme song, an obvious humorous anachronism.