In the vein of recent developments in extreme metal, noteable "thrash metal" in the early 80's a small number of groups started to play a slight variant of thrash metal which would slowly come to shape death metal. Proto-death metal so to speak.
Majorly influential records in the early stages include the early Hellhammer records, Posessed's Seven Churches, and various other records such as (then) hard thrashers Sepultura.
But when did death metal really become a stable genre?
There are two major years accompanied by very influential releases which are pointed as with being the "first" death metal records.
Death's 1987 debut "Scream Bloody Gore" is often pointed as being the first major death metal debut, featuring Chuck Schunilders signature death metal vocals. But the records had a very thrashy vibe.
This is why Morbid Angel's 1989 debut is considered the first pure death metal record, featuring a very proficient use of blast beats and relentless riffing along with David Vincent's majestic death metal vocals.
Death metal has since then been rapidly developing, and has inspired many sub genres. This thread will only be for the closest family of genres, example:
Technical death metal is allowed due to the technical tag being an addition rather than a fusion such as death metal and metalcore (deathcore).
Sorry for the spelling mistakes, I will try to clean up the mistakes later on.