I've gathered below some of my favorite quotations, presented in no particular order aside from some loose thematic clusters and juxtapositions. Please be aware that I've collected these over the years and have not tried in all cases to subject them to full scholarly fact-checking scrutiny, so I cannot always vouch for the accuracy of quotations I've run across in places other than original primary source locations. If you discover inaccuracies, I would be grateful if you would let me know.
You may also be interested in an additional collection of quotations about history collected by Ferenc Szasz of the University of New Mexico.