Complex sentence: At once he gave himself up to the most rigorous asceticism, violently defending the ideal of strict observance and orthodoxy, following the example set by St. Bernardine from 1420 onwards, he preached with great effect in numerous cities and eventually became well known.
Split into simpler sentences: At once he gave himself up to the most rigorous asceticism, violently defending the ideal of strict observance and orthodoxy, following the example set by St. Bernardine. From 1420 onwards he preached with great effect in numerous cities and eventually became well known.