Complex sentence: The rebels were lead by William the Conqueror's elder half-brothers Odo of Bayeux and Robert, Count of Mortain, with Odo the stronger of the two and leader behind the plot.
Split into simpler sentences: The rebels were lead by William the Conqueror's elder half-brothers Odo of Bayeux and Robert, Count of Mortain. Odo was the stronger of the two half-brothers and the leader behind the plot.