So when is Sof Zman Achila? And which part of the Galus Sof Zman Krias Shma/Tfila?
Hey, is that why there are so many late Minyanim these days — since we are anyhow after the Zman Tfila?
Anyhow, now we know what the Rishonim were doing in the ‘dark age’. It’s obvious. It was the Zman for Bedikas Chametz. So this is why the Yeshivos in Bavel were declining. You aren’t allowed to learn before the Bedika.