Church history

I have been reading Paul Johnson’s book A History of Christianity and found his version of the first 350 years strangely depressing.   I had never thought about the fact that people would so soon have tried to use Christianity for their own gain and to control others.  The struggle to come to terms with difficult theological issues was also not what I expected.

I think Constantine did Christianity no favors when he made being a Christian legal.  It was done for purely political reasons.  How do others feel about those who use Christianity for personal financial or political gain?  Have we not learnt any lessons?