Complex sentence: The war began in East Frisia due to a runaway feud between two major nobels Keno II tom Brok and Hisko Abdena, and all major parties in Friesland chose a side and a civil war arose.
Split into simpler sentences: The war began in East Frisia due to a runaway feud between two major nobles Keno II tom Brok and Hisko Abdena. All major parties in Friesland chose a side and a civil war arose.