Complex sentence: His cousin, Adelolf, Count of Boulogne, took his body for burial at St Bertin Abbey in Saint-Omer, and according to its annalist, Folcuin, king (sic) Eadwine had fled England "driven by some disturbance in his kingdom".
Split into simpler sentences: His cousin, Adelolf, Count of Boulogne, took his body for burial at St Bertin Abbey in Saint-Omer. According to the abbey's annalist, Folcuin, who wrongly believed that Edwin had been king, he had fled England "driven by some disturbance in his kingdom".