Complex sentence: Sir Cadogan is an eccentric knight who believes himself a mighty warrior, shouting at passerby and challenging them to duels, while appearing somewhat ridiculous, being unable to ride his horse and very bad at handling his sword.
Split into simpler sentences: Sir Cadogan is an eccentric knight who believes himself to be a mighty warrior, shouting at passerbys and challenging them to duels. He appears somewhat ridiculous, being unable to ride his horse and very bad at handling his sword.