There's a small quote rotator on the bottom of this and every page on the Codex, which I every so often add a contribution to. I started, simply enough, looking up quotes from some of my favorite leaders and thinkers in history, beginning of course with Marcus Aurelius, but soon found a serious number of quotes to be misattributed.
I came across a website of someone calling themselves the Quote Investigator, and being fascinated with research myself, I dug around for a while. I've learned to doubt all quotes. It's pretty clear that there are lots of misquotes, but just about everything appears to be suspect.
Making my quote collection has become much harder. I can't just attribute to Churchill something that was cobbled together from older quotes in disparate places. Further, it's notable how many seemingly common folk actually wrote things that are attributed to celebrities and "thinkers."
Below are the quotes that I've collected thus far. I'm always up for suggestions for new ones.