Complex sentence: It was a hard battel at the Lake of Vanern and many solders fell dead on the battelfield, acordently to the Gautreks saga And one of the fallen was King Sisar himself.
Split into simpler sentences: It was a hard battel at the Lake of Vanern and many solders fell dead on the battlefield. Accordantly to the Gautreks saga one of the fallen was King Sisar himself.