From The Inheritance of Rome by Chris Wickham, p. 35:
But given the weight of tax, and the endemic injustice that marked the Roman system, it is not surprising that corruption should focus on it. Social critics, more numerous as the empire went Christian and and a radical fringe of moralists gained a voice, very frequently stress fiscal oppression in their invective; only judicial corruption and sexual behaviour were as prominent. This would last as long as the empire.
Something to think about if you were wondering how long certain current conservative concerns, mixed with Christian religion, have been and will be with us.