Ehm, if you *do* want to go in all semantic (aside from the fact that Possessed was also formed in '83) here's some different info:
link and
link.
2nd links TL;DR quote:
Jeff: "Here's the story: Between [pre-
DEATH outfit]
MANTAS and the first
DEATH album [1987's
'Scream Bloody Gore'], [
DEATH leader]
Chuck [
Schuldiner] moved out to our fan club president's house to be around us. He's quoted in countless magazines that
POSSESSED is his primary influence. His album came out two years after
'Seven Churches', which was written in '82/'83.
There. I see myself out now. Ciao.