Please refer to the excellent answer above.
In line 375, Vico proclaims that poetry didn't originally begin as abstract, like many claim. He thinks that poetic wisdom was "a faculty born within [early humans]." He says that early poetry was viewed by ancients as "divine," and they were imagining all of their wants and uncertainties as being attributed to the gods. Thus, poetry was used as an explanatory device. Specifically, in 376, Vico says that poetry was used to explain things of nature. In 381, he goes on to say that Jove (God) was "born naturally in poetry as a divine character or imaginative universal...which must therefore all have been poetic by nature."
Vico's stance that God and religion are poetic creations of the human mind exemplifies his reasoning of the overall effect of humankind. Finally in 383 he overtly states, "from this sense springs another by which all peoples are naturally lead to do infinite honors to divinity. In this manner, the poets founded religions among the gentiles."