The pope in rome to arrange the marriage between ivan iii of russia and sophia, the niece of the last byzantine emperor. why might the pope have been disappointed with the results? a) the russian empire retained the eastern orthodox religion of the byzantine empire. b) the westward expansion of the great khan of the golden horde was stopped by ivan iii. c) as a result of the union, ivan iii and subsequent tsars converted to roman catholicism. d) ivan iii attacked rome and made it part of the russian empire in response to the pope's meddling.