Complex sentence: Crosses from graves at fortresses suggest that most Moravian chieftains converted to Christianity by the middle of the century, but the Frankish prelates described the Church in Moravia as "coarse" at their synod of 852.
Split into simpler sentences: Crosses from graves at Moravian fortresses suggest that most Moravian chieftains converted to Christianity by the middle of the century. The Frankish prelates described the Church in Moravia as "coarse" at their synod of 852.