this is a slippery slope, as you have in fact PALGERIZED, as you said so yourself, you passed it off as your own. That and your justifying, which means that you know it wasn't exactly correct to dothis.
However given that I do deal with things like this, and i am not getting to much from this simple explanation, I'll say it is iffy, you are right at the limits of bad taste/plagarism. If you had in fact said you got it off of google and wrote it into your own words and made it clear int eh rest of teh paper than that is somewhat acceptable. Basically in a history thesis statement you either argue for or against something.