Does Anybody Know What This Is From?

In the film "To Sir With Love", on his first day as teacher, Poitier asks his students to read something of their own choosing. One of them (the blonde girl) reads this, "And he had learned to love, I know not why, for this in such as him seemed strange".

That's as close as I can remember. Does anybody know what it is from please? I've tried googlehunting without success. Thank you.

It is Lord Byron.

http://www.imdb.com/title/tt0062376/quotes
http://www.nbu.bg/webs/amb/british/3/byron/childe3.htm

http://www.google.com/search?hl=en&rlz=1B3GGGL_enUS264US264&q=And<i>he+had+learned+to+love%2C+I+know+not+why%2C+for+this+in+such+as+him+seemed+strange+of</i>mood.&btnG=Search

Thank you bnauglen54 - that is a very long poem.