10% of ones income donated to a church, because the Pastor usually makes you feel bad if you don't give it. Taken from the Old testament example of Israel giving the Levites 10% of livestock because Levi didn't get a land inheritence. The Early Church in Acts however NEVER gave tithes, giving was free-will in the NT Church, The Roman Catholics re-introduced monatary tithes to finance their lavish lifestyles.