User blog comment:Xilinoc/Chapter 529 - Everything but the Rain, "The Rudiments"/@comment-6916556-20130306213048

This didn't happen 110 years ago. Aizen references shinji and his gang as already living in human world with hollowfied powers. On top of the fact Toshiro only became a shinigami not long before the series started, after rukia and renji did, so less than 40 years at the very least. I think this is in the frame of 25 years before the start of the series. Isshin Shiba is the captain in between the one that died and Toshiro