When the Arabs conquered much of the Middle East and north Africa, how did they treat non-Muslims? To what extent was there hostility between the different faiths, and when was the Islamic expansion welcome?

Answer 1

http://en.wikipedia.org/wiki/History_of_Islam

and

http://www.google.com/#hl=en&sugexp=les%3B&gs_nf=3&tok=g-nvD0pGXWE4sdDcAQ2oqQ&cp=10&gs_id=12&xhr=t&q=muslim+expansion&pf=p&tbo=d&output=search&sclient=psy-ab&oq=muslim+exp&gs_l=&pbx=1&bav=on.2,or.r_gc.r_pw.r_cp.r_qf.&fp=1d332d38cdc82502&bpcl=38625945&biw=1366&bih=643