Complex sentence: Mikołaj became famous for a vivid account of his eventful pilgrimage to the Holy Land published in 1601, and he converted from Protestantism to Catholicism, as later did his other brothers.
Split into simpler sentences: Mikołaj became famous for a vivid account of his eventful pilgrimage to the Holy Land published in 1601. He converted from Protestantism to Catholicism, as later did his other brothers.