What is the major theme of achebes novel arrow of god?

Main theme introduced by Achebe in Arrow of god is competition between tradition and christian faith.Achebe writes on the Nigeria in 1920's,when British came to colonize them. It moves through the downfall of Ezeulu, a priest of Ulu.Pride and Arrogance came sub themes for his downfall.In this novel, each and every people trying to come in to power and their ardent quest for authority lead to colonization. Achebe want to restore the lost prestige of Nigeria.