Existence of the Church
Lots of religions have arisen with false beliefs.
But:
nJesusŐ followers were completely demoralized by his death.
nWithin a short time they were boldly proclaiming his resurrection in the city where he was killed.
nMost of the apostles died as martyrs, not willing to retract their claims to have seen the risen Jesus.
nThe church expanded to fill the Roman Empire without use of military evangelism.