I can't find the source but it's stated as fact pretty much everywhere that Yamamoto founded the academy 2000+ years ago.
Which is weird, but that doesn't mean he was captain commander for 2000 years, he could of very well just been an instructor or simple captain. However it is fact he's been captain
commander for over 200+ years.
Heres a Renji reference, he was in the 2066 graduating class. Which is also weird, considering he seemed to have made the acad 2000 years to the present date not 2066 years. That must just be the graduating class number? The whole timeline is iffy.
http://www.onemanga.com/Bleach/79/23/
__________________
She completes my Equation.
Wakka wakka, who wants to hear a funny ass joke?