Thursday 13th July, according to some sources, was the Ancient Egyptian Festival to celebrate the Birthday of Ra.  Since Ra was the God of creation this could be interpreted as the day man was created!  Ra was also associated with the Sun and healing so perhaps it is no coincidence that the Roman’s celebrated Apollo on the same (Equivalent) date. 

Thursday 13th July in Roman Times was the culmination of the Games of Apollo.  As early as 212 BCE 13th July was the celebration of Apollo as the God of Healing (especially during wars) but this later extended into an 8 day festival ending on 13th July.  Apollo was associated with the Sun and his twin Diana (Goddess of Hunting) was associated with the moon.  Apollo became significant among the Romans when Augustus Caesar, as a young man, chose Apollo as his own god, and attributed his victory over Antony and Cleopatra to Apollo’s superiority over the Egyptian Deities!  Augustus is said to have described Apollo as: “Governor of Roman destiny; master of the sun; archer; augur; averter of pestilence; and giver of sound morals to the young.”