Research is vital. Not only in historical fiction, even. *shudders at horribly written, horribly researched novels where lazy author hide behind the idiotic "lol who cares about making stuff look realistic it's fantasy" excuse*
But, aye aye. If it's called historical
fiction there's a reason. And it's not like you can learn every little detail, ways of thinking, culture, morals, fashion, everyday life etc of past centuries overnight. It takes time. It takes the patience to read through mountains of apparently useless, hard-to-read academic stuff just to get a general overview of how life worked back then. And it takes far more than just googling around to find decent sources. Not that I'm bashing the Google, mind ya. I love it, I love Archive.org, I love Project Gutenberg and all the wonderful resources the internet, if used well, can provide just a few clicks away. Not to mention it's a treasure trove... Eh, scrap that, research itself is a treasure trove!
@ stamp message. And to all wannabe authors not bothering with the research: do your homeworks, guys!