While I do think the Ampeg 810 started the tradition, because they popularized 10s...they were no actually the first.
Pretty sure Traynor's YC-810 (Big B) predated the Ampeg design by a few years.
I actually learned to play through one of these and then later bought an MTI era SVT with the matching 810. I preferred the sound of the Traynor as it had sweeter mids and a bit more HF extension. The Ampeg was a bit fuller down low, but to my ears, every one I have played sounded muffled/muddy...and no amount of EQ can make it produce a tone I like.